Delay Analysis in Marshalling Yards: The case study of Malmö

CHRYSI KONTAXI

DEGREE PROJECT IN TRANSPORT SCIENCE

STOCKHOLM, SWEDEN 2020

KTH ROYAL INSTITUTE OF TECHNOLOGY

SCHOOL OF ARCHITECTURE AND THE BUILT ENVIRONMENT

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Delay Analysis in Marshalling Yards: The case

study of Malmö

by:

Chrysi Kontaxi

Supervisor:

Behzad Kordnejad

Examiner:

Albania Nissan

Master of Science Thesis TRITA-ABE-MBT-19643

KTH Royal Institute of Technology

Division of Transport Planning

June 2020, Stockholm, Sweden

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ACKNOWLEDGMENTS

I want to thank my supervisor, Dr. Behzad Kordnejad, from the bottom of my heart not

only for the confidence he has shown me in proposing to deal with this topic but also

for his support and guidance throughout my research. I am grateful for my cooperation

with such a remarkable and great scientist and human being. Collaborating alongside

with a person such as Dr Behzad Kordnejad is, you experience professionalism and

receiving great inspiration about what are you doing.

Special thanks to the operational manager of Green Cargo at Malmö, Marita Granqvist,

who greeted us very warmly during her service and had a very constructive

conversation about the topic. She provided us with much information that was very

helpful in writing and completing this thesis.

I would also like to thank Niloofar Minbashi for being an excellent guide in writing this

thesis and trusting me to undertake part of her study. While she always provided reading

material, photos and information to me.

Furthermore, I would like to thank the contributors of FR8HUB project. The aim of

that project was to increase punctuality, capacity, reliability, energy efficiency and it

was an important guide for my work.

Last but not least, I want to express my gratitude for my family’s support. Without

them, I would be not able to fulfil a dream of mine to come and study at KTH. To

express, also, my gratitude to my man, Antony, for supporting me in every step and

decision. Thank you!

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ABSTRACT

The management of terminal yards requires quite complex day-to-day operations when

hundreds of trains could be entered and/or exited marshalling yards every day. More

specifically, multi-dimensional decisions are necessary to be taken in daily basis for

management of operations. Manual solutions might cause inefficiency in the yard’s

operation and consequently to the network. Nowadays, many freight trains in Sweden

fail to follow their scheduled plan. In particular, a small portion of trains are following

the scheduled arrival and departure time while the majority of trains run ahead of

schedule.

This master thesis aims to conduct evaluation of internal procedures within a

marshalling yard in terms of time, examine the magnitude of delays from the scheduled

departure time, and to identify the key reasons causing the delay during departure and

their main implications. Furthermore, the master this aims to investigate ways of

optimizing operations to increase system punctuality. The Malmo’s marshalling yard

was used as a case study.

The methods are used for this master thesis are a qualitative as well as a quantitative

assessment. A literature review has been conducted using journal papers, conference

papers and technical reports from other relevant projects as well as on-site visit and

interviews. In order to manipulate the data for the research, the software Planimate was

used and a simulation model is built based on operations in Malmo’s marshalling yard.

Three scenarios are performed. The first one is considered without any usage of

automation. The second one, automation is applied in the case of the arrival yard and

the third one, automation is applied in the arrival and the departure yard.

The findings from the qualitative research show that there are several factors cause

delays, either network failures such as the late arrival of trains in the yard or internal

factors as the reduced railway capacity. Also, as the simulation model has been

demonstrated, any application of automated processes within the marshalling yard’s

operations will be beneficial because will speed up the internal processes. For instance,

the third scenario turns out the best scenario among the others because time is reduced

almost to half time compared to the first scenario.

Keywords: Delay Analysis, Malmo, Marshalling yard, Railways, Simulation.

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SAMMANFATTNING

Hanteringen av rangerbangårdar för godståg kräver ganska komplicerade dagliga

operationer när hundratals tåg kan komma in och/eller ut från dem varje dag. Mer

specifikt är flerdimensionella beslut nödvändiga att tas på daglig basis för att kunna

hantera verksamheten. Manuella processer kan orsaka ineffektivitet i bangårdens drift

och följaktligen för nätverket. För närvarande följer många godståg i Sverige inte sin

planerade tidsplan. En liten del av tågen följer den planerade ankomst- och

avgångstiden medan majoriteten av tågen går före schemat.

Detta examensarbete syftar till att utföra en utvärdering av interna förfaranden inom en

rangerbangård med avseende på tid, undersöka storleken på avvikelsen från den

planerade avgångstiden och att identifiera de viktigaste skälen som orsakar förseningen

under avresan och deras huvudsakliga implikationer. Dessutom syftar detta arbete till

att undersöka sätt att optimera operationerna för att öka systemets punktlighet. Malmös

rangerbangård användes som en fallstudie.

Metoderna som används för detta examensarbete är av kvalitativ såväl som av

kvantitativ bedömning. En litteraturöversikt har genomförts med hjälp av tidningar,

konferenshandlingar och tekniska rapporter från andra relevanta projekt samt besök på

plats och intervjuer. För att hantera data för forskningen användes mjukvaran Planimate

och en simuleringsmodell byggdes baserad på processerna i Malmös rangerbangård.

Tre scenarier undersöktes. I den första övervägs ingen användning av automatisering.

den andra, tillämpas automatisering när det gäller ankomstgården och i den tredje,

automatisering tillämpas vid ankomst- och avgångsgården.

Resultaten från den kvalitativa forskningen visar att det finns flera faktorer som

förorsakar förseningar, antingen nätfel som till exempel sen ankomst av tåg på gården

eller interna faktorer som minskad järnvägskapacitet. Som simuleringsmodellen har

visat, kommer all tillämpning av automatiserade processer inom rangerbangårdens

verksamhet att vara fördelaktig då det kommer att påskynda de interna processerna. Till

exempel blir det tredje scenariot det bästa scenariot bland de andra då tiden reduceras

nästan till halvtid jämfört med det första scenariot.

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CONTENTS

ACKNOWLEDGMENTS ........................................................................................................................ 2

ABSTRACT .......................................................................................................................................... 3

SAMMANFATTNING ........................................................................................................................... 4

LIST OF FIGURES ................................................................................................................................. 7

LIST OF TABLES ................................................................................................................................... 8

ABBREVIATIONS ................................................................................................................................. 9

1. INTRODUCTION .............................................................................................................................. 1

1.1 BACKGROUND ........................................................................................................................... 1

1.2 RESEARCH QUESTIONS AND OBJECTIVES .................................................................................... 3

1.3 METHODOLOGY ........................................................................................................................ 3

1.3.1 Qualitative Assessment ....................................................................................................... 3

1.3.2 Quantitative Assessment .................................................................................................... 4

1.3.3 Delimitations ...................................................................................................................... 4

2. LITERATURE STUDY ON RAIL FREIGHT STATIONS ............................................................................ 5

2.1 MARSHALLING YARDS ............................................................................................................... 5

2.2 CLASSIFICATION OF MARCHALLING YARDS ................................................................................. 6

2.3 SERVICE LEVEL AND QUALITY PARAMETERS ............................................................................. 12

2.3.1 Service level ...................................................................................................................... 12

2.3.2 Quality Parameters ........................................................................................................... 12

2.4 BASIC DESIGN PRINCIPLES........................................................................................................ 12

2.4.1Classification tracks ........................................................................................................... 13

2.4.2 Secondary traffic classification .......................................................................................... 14

2.4.3 Comparison with marshalling yards in Europe ................................................................... 15

2.5 BASIC PRINCIPLES OF OPERATION ............................................................................................ 18

2.5.1 Security ............................................................................................................................ 19

2.5.2 Delays .............................................................................................................................. 20

2.5.3 Staff ................................................................................................................................. 21

2.5.4 Maintenance ................................................................................................................... 21

2.6 PROBLEMS DURING OPERATION PROCEDURES INTO THE MARSHALLING YARD ....................... 21

2.6.1 Switch engines .................................................................................................................. 21

2.6.2 Failure in the order of train wagons ................................................................................. 22

2.6.3 Re-switching .................................................................................................................... 22

2.6.4 Failures on the equipment ................................................................................................ 23

2.6.5 Staff ................................................................................................................................. 23

2.6.6 Extreme weather conditions ............................................................................................. 23

2.6.7 Hazardous material handling ............................................................................................ 24

2.6.8 Expediting priority shipments ............................................................................................ 25

2.6.9 Derailments ...................................................................................................................... 25

2.7 NETWORK PROBLEMS RESULTING FROM MARSALLING YARD OPERATIONS ............................. 26

2.7.1 Train cancelations and late departures ............................................................................. 26

3. CASE STUDY OF MALMÖ MARSHALLING YARD - GENERAL INFORMATION ................................... 27

3.1 GENERAL INFORMATION ABOUT MALMÖ’S MARSHALLING YARD ............................................ 27

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3.2 TRAIN OPERATORS .................................................................................................................. 30

3.3 THE DESIGN AND FUNCTION OF THE MASHALLING YARD ......................................................... 30

3.4 RAILWAY TRAFFIC.................................................................................................................... 32

3.5 MARSHALLING ........................................................................................................................ 32

3.6 STAFF ...................................................................................................................................... 32

3.7 LIMITATION ON TRAINS LENGTH ............................................................................................. 33

4. MALMO’S MARSHALLING YARD – DELAY ANALYSIS ..................................................................... 35

4.1 STUDY VISIT AT MALMÖ’S MARSALLING YARD ......................................................................... 35

4.2 MODEL STRUCTURE DESCRIPTION ........................................................................................... 42

4.2.1 Sub-systems of the model ................................................................................................. 49

4.3 SIMULATION RESULTS ............................................................................................................. 52

4.3.1 Scenario: No automation .................................................................................................. 52

4.3.2 Scenario: With Automation ............................................................................................... 53

4.3.3 Scenario: Automation of additional procedures ................................................................. 53

5. CONCLUSION ................................................................................................................................ 55

5.1 DISCUSSION ............................................................................................................................ 56

5.1.1 LIMITATIONS .................................................................................................................... 57

5.3 FUTURE RESEARCH .................................................................................................................. 58

REFERENCES ..................................................................................................................................... 59

APPENDIX ........................................................................................................................................ 65

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LIST OF FIGURES

FIGURE 1: DISTURBANCE HOURS DUE TO DEPARTURE DELAYS 14 YARDS/STATION. (FREIGHT, 2018) ........... 2

FIGURE 2: A COMMON LAYOUT OF A MARSHALLING YARD INCLUDING A HUMP. (KHOSHNIYAT F. , 2012) ..... 6

FIGURE 3 ADVANCED LAYOUT OF A HUMP YARD (JACOB, 2011) ................................................................ 8

FIGURE 4 DOUBLE-ENDED HUMP YARD (JACOB, 2011) ........................................................................... 8

FIGURE 5 SINGLE-END HUMP YARD (JACOB, 2011) ................................................................................. 9

FIGURE 6 DEVELOPMENT OF COSTS OF RAIL FREIGHT WITHOUT AND WITH AUTOMATIC COUPLING VS. TRUCK

2018 – 2030 (2018 = 100%) (OLSSON, 2017) ............................................................................ 11

FIGURE 7 MARSHALLING YARD IN NIS (SERBIA) (SHIFT2RAIL, D4.1 IDENTIFICATION OF RELEVANT

INFORMATION ABOUT TRAIN CLASSIFICATION PROCESS AND MARSHALLING YARD SORTING

METHODS, 2019) ....................................................................................................................... 15

FIGURE 8 MARSHALL YARD OF KARBONAT (BULGARIA) (SHIFT2RAIL, D4.1 IDENTIFICATION OF RELEVANT

INFORMATION ABOUT TRAIN CLASSIFICATION PROCESS AND MARSHALLING YARD SORTING

METHODS, 2019) ....................................................................................................................... 16

FIGURE 9 MARSHALLING YARD OF LAUSANNE TRIAGE (MARTON, 2009) ................................................. 17

FIGURE 10 HALLSBERG MARSHALLING YARD (ARC, 2017) ................................................................. 17

FIGURE 11 MALMÖ YARD (SHIFT2RAIL, DELIVERABLE 3.1: REAL TIME NETWORK MANAGEMENT AND

SIMULATION OF INCREASING SPEED FOR FREIGHT TRAINS, 2018) ................................................. 27

FIGURE 12: OVERVIEW OF THE RANGE OF THE MARSHALLING YARD, BLUE SCRAPING CORRESPONDS TO

GEOGRAPHICAL DEMARCATION LEVEL 1, YELLOW DOTTED LINE LEVEL 2. (TRAFIKVERKET,

RISKANALYS MALMÖ RANGERBANGÅRD, 2013) ......................................................................... 28

FIGURE 13: LOCATION OF THE MARSHALLING AREA, WORKSHOP AND ENTRANCE AREA (TRAFIKVERKET,

RISKANALYS MALMÖ RANGERBANGÅRD, 2013). ........................................................................ 31

FIGURE 14: IT EQUIPMENT OF THE OPERATOR IN THE CONTROL TOWER ................................................. 36

FIGURE 15: TRACK FOR FOREIGN FREIGHT TRAINS (LEFT SIDE)............................................................... 37

FIGURE 16: THE HUMP IN THE MARSHALLING YARD OF MALMÖ .............................................................. 38

FIGURE 17: DOUBLE SIDED BEAM BRAKE - HUMP BEAM BRAKE ............................................................... 40

FIGURE 18: DOUBLE SIDED BEAM BRAKE - HUMP BEAM BRAKE ............................................................... 41

FIGURE 19 GENERAL STRUCTURE OF THE SIMULATION MODEL (KHOSHNIYAT, 2019) IS MODIFIED AND

INCLUDES ALL THE PROCESSING STAGES ....................................................................................... 43

FIGURE 20: SCHEMATIC REPRESENTATION OF THE FLOW IN A MARSHALLING YARD.................................... 48

FIGURE 21: ARRIVAL SUB-SYSTEM ........................................................................................................ 49

FIGURE 22: ARRIVAL SUB-SYSTEM ........................................................................................................ 50

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FIGURE 23: CLASSIFICATION SUB-SYSTEM ............................................................................................ 50

FIGURE 24: DEPARTURE SUB-SYSTEM .................................................................................................. 51

FIGURE 25: SCENARIO 1 – TREND PERFORMING BASED ON ARRIVAL TIMES ............................................... 52

FIGURE 26: COMPARISON BETWEEN SCENARIO 1 (NO AUTOMATION) AND SCENARIO 2 (WITH AUTOMATION)

................................................................................................................................................ 53

FIGURE 27: COMPARISON BETWEEN SCENARIO 1 AND SCENARIO 3 (AY: ARRIVAL YARD, DY: DEPARTURE

YARD) ....................................................................................................................................... 54

FIGURE 28 APPROXIMATE TIME TO PREPARE A TRAIN FOR SHUNTING ...................................................... 65

FIGURE 29 DEDICATED TIME TO DIFFERENT OPERATIONAL TASKS ................................................. 65

FIGURE 30 DEDICATED TIME TO SEVERAL TASKS BEFORE DEPARTING ................................................. 66

LIST OF TABLES

TABLE 1 COMPARISON BETWEEN YARD TYPES (MARINOV, 2014) ............................................................ 11

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ABBREVIATIONS

AY Arrival Yard

DY Departure Yard

EU European Union

S2R Shift2Rail

WP Work Package

FIFO First In First Out

YM Yard Manager

RU Railway Undertaking

IM Infrastructure Manager

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1. INTRODUCTION

1.1 BACKGROUND

Railway freight plays a significant role in transportation for many companies that

demand to transfer their goods, and the choice of using rail is beneficial in terms of low

cost and low environmental impact. To optimize freight transportation services, the

increment of punctuality in the railway network is essential. Different factors affect the

punctuality of freight trains such as as the number of marshalling yards that are going

to be used during train formation processes (Dirnberger, 1995).

Hundreds of incoming/outgoing trains, vast and complex yard operations are carried

out in case of the management of terminals and yards Large freight nodes consist of a

complex infrastructure of tracks, switches, crossings and infrastructure service facilities

(Bohlin Markus, 2012).Therefore, multi-dimensional decisions are required for the day-

to-day management of operations that might be extremely complex for manual

solutions causing inefficiency in the yard's operations and consequently to the network.

Inadequate operation or maintenance of the marshalling yards can have different

consequences depending on how much impact this will have on the traffic of the leading

rail network. For instance, if a marshalling yard cannot be used to its full capacity,

additional costs will arise for the operators, which must be handled in order to identify

an alternative route. However, this situation can also result in customer losses due to

delayed deliveries.

Some of the consequences that may arise from delays within a yard are the following

(Nelldal, 2004):

Additional costs for customers and operators could emerge due to delays that

might occur.

From the system’s perspective, additional costs may be observed due to the

rerouting of freight trains to another marshalling yard where the capacity of the

network is higher.

Damages to wagons and on goods can occur due to insufficient maintenance, the

total cost for customers and operators may be increased as well.

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Nowadays, in Sweden, many freight trains fail to follow their scheduled plan. Many

trains run ahead of schedule, but only a small portion of trains are following the

scheduled arrival and departure time. For this reason, marshalling yards and the railway

network must improve their interaction. There is a need for better planning and control

of freight traffic in the Swedish network, and the scheduling of the timetable needs to

be characterized by flexibility in order to meet the needs of freight traffic.

In Sweden, the punctuality is measured by the disturbance hours and the affected areas.

According to the Swedish Transport Authority (Trafikverket, The Swedish Transport

Administration - Annual Report, 2017), in some areas, the highest number of

disturbance hours are caused by departure delays. Specifically, Malmö is ranked first

among the other marshalling yards with the highest number of late departures. The areas

and their disturbance hours can be observed in Figure 1.

Figure 1: Disturbance hours due to departure delays 14 yards/station. (Freight, 2018)

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1.2 RESEARCH QUESTIONS AND OBJECTIVES

In this thesis, we are trying to answer in the following research questions (RQ):

RQ1: Are delays of the departing trains caused mainly due to the late arrivals of

incoming trains or due to the internal processes on the yard? Regarding the latter,

which are the root causes of delayed processes?

RQ2: If an incoming train arrives delayed, is there any possibility to secure the

scheduled connection by reducing the total time during the yard operation?

RQ3: What measures can be considered in order to reduce the effect of late

arrivals (if late arrivals contribute to the delayed departure of a train)?

RQ4: Can new technologies contribute positively to the increment of the

punctuality (e.g. automation of processes in the yard)?

The main objective of this thesis was to conduct evaluations for the Malmo’s yard in

terms of time, evaluate the magnitude of delays from the scheduled departure time, and

to identify the key reasons causing the delay during departure and their main

implications. Furthermore, we studied the ways of optimizing operations to increase

system punctuality.

1.3 METHODOLOGY

1.3.1 Qualitative Assessment

During this thesis, an extensive literature review has been realized. The literature

review has been conducted using documents from the websites, journal papers,

conference papers and technical reports from projects. We gathered and analyzed this

material in order to have a deeper understanding of the research field.

To meet our objectives, interviews have been conducted with the rail and yard operator

of the Green Cargo and the Swedish infrastructure manager from “Swedish Transport

Administration”.

The Marshalling Yard Manager (YM) and the Freight Train Operator/ Rail

Undertakings (RU) and the Infrastructure Manager (IM) as stakeholders play an

essential role in the marshalling yard. These interviews enabled a deeper understanding

of the current situation and on the existing problems in Malmö’s marshalling yard

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operations. The interviews were carried out by email and skype, as well as a study visit,

has been realized.

1.3.2 Quantitative Assessment

In order to manipulate the data for our research, the software Planimate (Planimate,

2019) was used. We used this software to build our simulation model. Planimate allows

the simulation of a process as a set of discrete events, in series or parallel, utilizing

hierarchical networks.

1.3.3 Delimitations

In this thesis, we considered the Malmö’s Marshalling Yard, and we have faced with

some delimitations, as the following:

Lack of previous studies related to delays in Malmo’s marshalling yards. The

reference to previous research studies is the basis of this literature review and

helped us to clarify the research problem that is being investigated. It is important

to mention that, as a reference to the subject of this thesis, there was a small

sample of studies in the literature regarding Sweden.

Access to adequate data. An essential part of this study depended on access to

individuals, organizations and data or documents that needed to be retrieved by

organizations by limiting the research process.

Language barrier. The conducted research was related to the current situation

of a marshalling yard in the Swedish territory. The author was referred to Swedish

documents which required a certain amount of time in order to be translated

adequately since the author had basic Swedish knowledge and therefore has

experienced difficulties in reading and interpreting in the Swedish language.

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2. LITERATURE STUDY ON RAIL FREIGHT STATIONS

According to (Uppenberg, 2010) a railway station is “any installation where a track

change is available and where the trains depart, end, rebound or maneuver”. Also, a

railway station is an installation where an interface between two transport modes of

which at least one comprises the rail. At railway stations, boarding/disembarkation

procedures of passengers and loading/unloading of goods are carried.

Railway freight stations are “the nodes where goods get into or out of the railway

network, rail wagons get classified, and freight trains get sorted” (Caprara, 2011). Also,

the stations play a significant role in the railway freight transport organization.

However, with the development of social economy, the traditional transport

organization based on the scattered layout of railway freight stations could not be

adapted to the tendency of the freight transport intensive development. Therefore, the

existing problems in the operations of railway freight stations include insufficient

shipment, the inefficient operation, and the delay of goods and the waste of transport

resources.

Depending on whether it serves passengers or freight, railway stations are divided into

three major categories: passenger, freight and mixed (serving both).

Depending on the size and volume of the traffic being handled, the railway stations are

divided into small, medium and large.

2.1 MARSHALLING YARDS

In rail freight transport, the marshalling yard is essential. The reliability and the

efficiency of a rail freight service are influenced by the efficient usage of the marshal

yards. Thus, the transportation cost can be reduced, and the punctuality and the

reliability can be increased. The important processes of yards are the disassembly and

the assembly of the trains depending on the destination of their tracks. Specifically, the

wagons of incoming trains are disaggregated in order to be formed in a new

composition of trains through a system of tracks and switches. The outgoing trains are

produced through a track system and by using switches (Shift2Rail, D4.1 Identification

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of relevant information about train classification process and marshalling yard sorting

methods, 2019).

The primary operations of marshalling yards are summarized as follows (Shift2Rail,

D4.1 Identification of relevant information about train classification process and

marshalling yard sorting methods, 2019):

(1) Sorting of wagons by destination.

(2) Combine them on trains.

(3) Form new trains for easy wagon departures.

Most of the marshalling yards consist of three significant sub-yards, as shown in Figure

2:

(1) An arrival yard (AY). They have a hump between the arrival and the classification

yard and rely on gravity and switching systems to transport the cars from the top

of the hump to the desired classification track.

(2) A classification bowl (CB) or Classification Yard (CY).

(3) A departure yard (DY).

Figure 2: A common layout of a marshalling yard including a hump. (Khoshniyat F. , 2012)

2.2 CLASSIFICATION OF MARCHALLING YARDS

2.2.1 Hump yards

They are the largest and the most effective type. Also, they have the most significant

shunting capacity. The main part of them is the hump. The hump yard can handle three

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to four times the number of wagons in order to manage the best flat yard. At the subway

yard, the arrival and sorting of lines are successive. They can be made with a minimal

slope or a steep slope, as the track change area is approached. When the car is

disconnected from the wagons after being disengaged to the hub area, they slowly roll

towards the end of the sorting lines and stop in front of other wagons that are already

in the lead. (Marinov M. a., 2014).

If there are successive wagons for the same sorting line, it is not necessary to be

disconnected from each other. The top of the hive is in the trajectory between the arrival

and sort lines. A manoeuvring machine is placed behind the train on the arrival line and

pushes it to the hub. It is a continuous process where there is no need to reverse the

course throughout its short duration. Moreover, it is noticed that the processes for

configuration of freight train and design of marshalling yards have almost been the

same for the last decades, apart from some few exceptions and introduction of new

technologies (Samuel, 1961).

The change of a trajectory can only be done when the first subset has passed entirely

from it. The subsets are under the same inclination and maintain a constant speed, but

the speed varies according to the weight, the braking force imposed by the engine on

the vehicles and the number of wagons in each subset. Therefore, further action is

required to maintain the distance between the sub-groups (Fitchew, 1967).

The level of the sorting lines continues to have a slope so long that the first wagon that

enters the line runs to its end. In the case of curved segments, a stronger slope is given

to the outer lines to balance the resistance received by the wagon wheels due to the turn.

Straight lines at the centre of the station are better suited for the arrival of empty wagons

that do not run as well as the loaded ones. The sorting lines must be flat towards the

end of their length and then ascend slightly towards the end of the departure lines

(Fitchew, 1967) (Peter Marton, 2009).

Several tracks are called "fridge tracks" which are dedicated to the trains that cannot be

assigned immediately to a track when it is humped and for which the scheduled train

departure time is not near to the future. These trains can be placed in the fridge tracks,

and then they will retry to hump (Djellab, 2010).

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In Figure 4, the classification tracks relate to the departure yard at the end of the other

hump. However, all yards do not have to arrive and departure tracks. Because there are

cases that have single-ended classification bowls such as Figure 5. Also, some cases

include a secondary hump their opposite end. However, the most common design for

the hump yards is Figure 3 (Jacob, 2011).

Figure 3 Advanced layout of a hump yard (Jacob, 2011)

Figure 4 Double-ended hump yard (Jacob, 2011)

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Figure 5 Single-end hump yard (Jacob, 2011)

The efficient operation of a rail freight transport system requires the use of a small

number of sorting stations. The concentration of work, therefore, requires stations

capable of managing many wagons, and hence the filling stations that meet these

requirements should be the most widespread type of marshalling yards (Crane, 1995).

2.2.1.2 Flat Yards

They are made out on flat ground or a slope. In this type of yards, the freight cars are

pushed to reach their required location. In this type of station, sorting lines are

terminating at one end. Wagons are propelled from the top of the line bundle by

changing the track to the appropriate sorting line according to the destination of the

leading wagons. After the wagons are detached from the train, the manoeuvring

machine moves on the contrary by pulling the other wagons in the area of the track

change. The changes are correctly placed, and the machine pushes the next wagons to

the sorting line assigned to their destination. The process continues until all wagons

have entered the specified sorting lines. The main drawback of the station levels is the

frequent reversal of routing required by the manoeuvring machine. This limits the

number of wagons that can be managed in each time. The disadvantages of the flat

yards are as follows (Marinov M. , 2009):

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a) Discontinuation of the sorting process when a train is removed from the sorting

lines since it must pass through the area of the track changes.

b) The delay of the departure trains from the sorting lines is resulting from confusion

with the sorting process. When the arrival lines are adjacent to the sorting lines,

they are called parallel. When the arrival and sort lines are on either side of the

track change section, they are designated in series.

2.2.1.3 Gravity yards

They are similar to hump yards. This type of yards is set up on a falling gradient.

In some stations, the falling gradient extends along the lines of arrival along their entire

length. Before disconnecting the engine on the arrival line, the brakes shall be applied

to enough front wagons to prevent the train from moving until the preliminary

procedures are completed.

Wagons end up approaching and resting on immobilized wagons, facilitating the

disconnection of subsets. When sorting can begin, the brake is released into the first

wagons, and the train starts to roll forward under the influence of gravity. In the track

changing section, the slope becomes steeper so that the space between the sub-

assemblies allows the needles to be changed. In the sorting lines, the slope performs the

same work as the hydrated stations.

The advantage of pure gravity stations is that they can work without the use of a

manoeuvring machine. However, they are usually constructed in natural locations

where the soil specificity reduces the required earthworks. Otherwise, construction

costs would be prohibitive (Marinov M. a., Curriculum development and design for

university programmes 301 in rail freight and logistics, 2014).In Figure 6 it is shown

the estimated development of costs of rails freight without and with automatic

coupling vs truck from 2018 to 2030 (Olsson, 2017).

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Figure 6 Development of costs of rail freight without and with automatic coupling vs. truck 2018 –

2030 (2018 = 100%) (Olsson, 2017)

Table 1 Comparison between yard types (Marinov, 2014)

Yard Type Features Advantages Disadvantages

Hump yard The main part is the

yard. In comparison

with the flat yards, they require cars to

be hauled by

shunting engines. It includes receiving

yard, classification

bowl, departure yard.

Large.

More effective

classification

yard.

Largest shunting

capacity.

There is no need

for tractions

locomotives.

Require more

staff, e.g. to set

the brakes.

The investment

cost for the hump must be

compared to the

staff costs.

The hump itself.

If the number of

humps is not

enough as the switch engines, it

is possible to

deal with a

bottleneck.

Flat yard These are

constructed on flat

ground or on a gentle slope.

Need for traction

locomotives.

Staff is required.

Bottlenecks can

occur on

shunting necks.

Gravity yard Like hump yard but

there is a continuous

falling gradient. Although they have

topographical

differences.

Need less usage

of engines. Only

one engine is

needed to push the wagons to the

hump.

Cheaper than the

others.

In most of the cases,

it has the same

disadvantages as hump yards.

12

No need for

tractions

locomotives.

Most of the yard that were build the last decades are single-ended yards in which a

multistage sorting can be realized.

2.3 SERVICE LEVEL AND QUALITY PARAMETERS

2.3.1 Service level

The service level offered by a marshalling station is determined based on specific

quality parameters. Depending on the extent to which these parameters are met, the

service level of the sorting station is assessed and characterized.

2.3.2 Quality Parameters

The basic quality parameters of a marshalling yard (Kendra, 2013):

o Automation

o Damage to transported goods

o Deceleration speed of trains in subsets

o Dynamic marshalling yards

o Capacity of marshalling yards

o Operating costs of sorting station

o Preparation time

o Traffic Analysis

o Wagon stay time at classification yard

o Wagon wear

o Sorting ability

o Sorting station efficiency

2.4 BASIC DESIGN PRINCIPLES

13

The main design principles that are based on classic and new approaches are described

in the following subsections.

2.4.1Classification tracks

The main track’s classification includes the arrival yard and the departure yard.

The arrival yard and its track are useful pieces of the infrastructure since they allow

incoming trains to remain outside the main marshalling area and tracks traffic, as long

as they wait to be sorted.

Departure yards can be justified when there are wagons that cannot depart immediately

while they are registered. Their stay may be due to problems with the occupation of the

track, waiting for a machine or other causes. Once a wagon reaches the arrival yard

until it is part of a train on a sorting line there is a break on its movement. It is desirable

to have no further delay beyond that. A sorting line must be discharged otherwise

sorting is delayed. In case of departure tracks, two functions should be released:

(AUTH, 2018)

1. Allow trains to be traversed from the sorting bundle, once their composition has

been completed, in such a way that it does not interrupt the operations of passing

through the hull

2. Permitting the operations related to the departure and temporary stay of the

trains waiting to be promoted on the railway network.

The absence of departure yards is an additional incentive for fast forwarding of wagons

to their destination. In case that there are departure tracks, continuous care is required.

In the location that the wagons will be sorted, the essential requirement is to connect

the tracks into which they can enter. If some lines are attributed to specific trains, they

are designated as fixed distribution lines. Fixed distributions may allow a line to be

used for specific destinations for a part of the day and others for the rest of its duration.

Fixed distributions simplify distribution and minimize errors (Hugh, 1961).The sorting

lines should have a slightly longer length than the longer trains that are expected to

depart from them. If their length is exactly equal to that of the trains, the last wagons

should enter the line at a shallow speed to avoid intense collisions, which reduces the

sorting speed. More extensive lines are usually mapped to the destinations where the

longest trains are heading. When wagons in one line fill the train, they are required to

be removed immediately so that the line is available for re-use and avoid unnecessary

delays (Marinov, 2014).

14

The required number of sorting tracks depends on the number of sortation expected at

the station. A common problem is the lack of sorting lines, which leads to the use of a

line for more than one screening, and further deflection of the wagons for their complete

separation. Alternatively, a yard with very few sorting tracks, even though it accepts

several wagons for specific destinations, it can move them through man oeuvres to these

points, merge them and send them to another marshalling yard for the final sorting. As

this process forces the wagons to pass through an additional sorting station, it extends

their transport time, increases the probability of damage and increases the cost of their

handling (Pirgidis, 2006).

Small radius curves would make sorting lines unsafe for some vehicles. As the number

of lines increases, the distance between the hub and the track changes as the most distant

lines increased. This also limits the number of sorting lines that are available for use. If

the distance increases very much, sorting is delayed. There is a reunion of the lines as

they are connected to the exit line or departure lines (Pirgidis, 2006).

2.4.2 Secondary traffic classification

Secondary sorting can take place on the main classification lines. However, in stations

with high traffic, the existence of secondary sorting lines is justified. This will allow

for secondary sorting without impeding the departure of trains from the main sorting

lines or their classification within them.

2.4.2.1 Hump

Trains arriving at the arrival yard carry wagons for any destination. A single sorting

line can serve a destination. For this reason, during the sorting process, each wagon

passes through a common line segment that connects to all sorting lines. In this case, if

there is an elevation to speed up screening with gravity, it is called hump.

In small stations, the passing of the vehicles from one line to another is realized after

constant association using a maneuvering line. In the cabin, the trains are pushed by

their vehicles unbuttoned. Then, with the help of gravity, the vehicles roll to the desired

destination line (after properly adjusting the relevant line breaks). For the regulation of

the running speed, special brakes mounted on the line act on the wheels of the vehicles.

Modern yards are equipped with sensors that control the speed and acceleration of

wagons as well as their weight and impose the necessary braking to stop the wagons at

the desired point. (Marinov, 2014)

15

2.4.3 Comparison with marshalling yards in Europe

(1) Marshalling yard Nis in Serbia on Corridor X (Shift2Rail, D4.1 Identification of

relevant information about train classification process and marshalling yard sorting

methods, 2019) in shown in Figure 7.

It is a yard with a parallel arrangement of tracks in the city of Nis and it has three

magisterial railway lines which are included in the pan-European Corridor X.

There are 36 tracks which are divided in four categories:

(i) receiving-departure (Track 2 to Track 9)

(ii) shunting-dispatch (Track 10 to Track 28)

(iii) station (Track 29 to Track 36)

(iv) bypass track-first (Track 1a to Track 1b).

The shunting operations realized by shunting diesel locomotive. It pushes the

freight cars to the required tracks.

Figure 7 Marshalling yard in Nis (Serbia) (Shift2Rail, D4.1 Identification of relevant information

about train classification process and marshalling yard sorting methods, 2019)

(2) Marshalling yard Karbobat in Bulgaria on the Corridor VIII.

This yard serves cargos' and passengers' movement and it is able to perform the

disassembly and the assembly of the freight trains.

16

It has a parallel arrangement of tracks with two regions with 35 tracks. The tracks

are divided in three categories:

(i) receiving-departure (from Track 1 to Track 5, From Track 21 to Track 27),

(ii) shunting-dispatch (from Track 6 to Track 17, Track 29 to Track 35)

(iii) wagon tracks (from Track 18, Track 28).

Figure 8 Marshall yard of Karbonat (Bulgaria) (Shift2Rail, D4.1 Identification of relevant information

about train classification process and marshalling yard sorting methods, 2019)

(3) Marshalling yard in Lausanne Triage

It has a receiving yard, a classification bowl of 38 tracks with two parallel hump

tracks but there is no separate departure yard.

Ten tracks reserved to form freight trains.

17

Figure 9 Marshalling yard of Lausanne Triage (Marton, 2009)

(4) Hallsberg marshalling yard

It is the biggest yard in the Nordic countries

It has an arrival yard with 8 tracks which is connected to the Classification yard

via a double hump. The classification yard has 32 tracks. The departure yard

has 12 tracks.

Figure 10 Hallsberg marshalling yard (ARC, 2017)

18

2.5 BASIC PRINCIPLES OF OPERATION

Major operations steps in marshalling yards are planned as follows (Boysen, 2012):

Prior information for inbound and outbound trains;

Check in of the incoming trains;

Disassembly/Assemblage of trains;

Shunting of wagons inside the yard;

Usage of hump and/or locomotive for wagon’s movement;

Check out and departure of outbound trains.

Trains, that are going to be processed, shunting to classification bowl. But prior is

conducted a technical and commercial wagon’s investigation, that take place the

checking of train’s composition, the preparation for disaggregation and later the

procedure for the removal of certain secondary technical breakdowns. Trains that are

not going to be processed in the yard, i.e. transit trains that are arriving at the departure

yard, they are following the same processes as they were mentioned above. In some

cases, it is necessary the locomotive to be changed on the transit trains.

According to (Boysen, 2012) after the train arrives at the yard, an investigation for

technical malfunctions is carried out by the staff. This is intended to distinguish and

dispose of failures that put traffic safety in jeopardy. The wagons from the train unit are

not disconnected in the event of a slight defect. In the event of a malfunction due to a

technically non-functional / incorrect startup, the staff who inspects the wagons shall

write down the labels appended on the wagon and shall notify the manager.

The porter and the guard carry out some checks to detect and remove any defects in

either the goods or the accessories of the wagons, which may threaten the safety of the

goods, the personnel and the other operations of the yard. The whole train is inspected

twice, one after the train arrives in the yard and the second time just before the train

leaves the yard.

The normal processing of transit trains is running the following task: Employees shall

be on the arrival track in order to pick up some data related to train’s composition and

the entry time, just before the train arrives.

19

After the train arrives at the arrival yard the tasks are carried out are the following:

Disconnect and exit of train’s locomotive.

Delivery of documentation.

Review and connect to the shunting locomotive.

Commercial investigation.

Technical and damage inspection of the wagons.

Dispatches from the marshalling yard.

The classification bowl consists of the following activities:

Disconnection and exit of train locomotive.

Determining the exact composition of the train.

Commercial and technical investigation of the train.

Preparation for maneuver.

Entry and connection with the train locomotive.

Commercial and technical investigation of the train and the wagons.

Constructing a travel statement and its annexes which are delivered to the train

personnel.

Departure from the marshalling yard.

2.5.1 Security

The safety of a railway system means "ensuring through the system components that in

the course of operation the level of risk cannot be characterized as unacceptable"

(according to certain levels of risk). In any case, the transition from a higher level of

risk to a lower (eg from undesirable to tolerable) requires additional security measures,

which inevitably leads to higher initial investment costs but also operation and

maintenance of the system (Samuel, 1961) (El Koursi, 2010) (Peng, 2016)

European rail safety policy through the Directive 49/2004 (Eur-Lex, 2004) covers four

key areas:

a) Reviewing and harmonizing the content of safety rules at European level

20

b) Removing remaining barriers to further market opening.

c) Ensuring transparency, information, and implementation of the appropriate

procedure in railway legislation.

d) The investigation of serious accidents and incidents.

2.5.2 Delays

There are considerable delays in dispatching, handling and receiving products from one

marshalling yard to another. The measures to reduce delays proposed by (Gaentatzi,

2009) are the following:

Promote the fastest oncoming trip: Sending wagons directly to their destination

if it is possible in order to avoid unnecessary stopovers. Motion analysis also

plays an important role here. The shipping details contained in the analysis

indicate whether there is room for additional direct services in order to reduce

downtime. If traffic cannot be driven directly to its destination, it must pass

through the minimum number of sorting stations after it leaves its original station.

Rapid shipment of trains: The failure of a train's exact time not only risks the

passage of the wagons of this train but also of the wagons of other trains.

Departures are often successive. Thus, delayed departure of a train of a sequence

may be delay also the followed trains, causing long delays in the main lines. If

there is an opportunity in daily operation to improve scheduled categorization, it

must be exploited, as the better maximum speed than the planned it helps to

decrease the recovery time after delays.

Rational use of sorting stations: It is necessary to avoid the unnecessary entry

of wagons into stations, as well as the interruptions of wagon traffic when

entering grading stations cause delays. Wagons should only pass through stations

when it is inevitable. The design of commercial trains should be provided for

direct services between stations and lines where it is possible. This not only

avoids delays in sorting stations but also reduces the cost of handling wagons. A

wagon when enters to a sorting station is charged with a percentage of the station's

operating costs. This cost, as has been confirmed, as scary. By keeping unattended

wagons out of the station, the rest can be managed easily. It is also observed that

21

more detailed recording of wagon movements is necessary, but if this is not

possible, the best method is to check the sorting stations periodically.

2.5.3 Staff

At a sorting station, it is advisable to have enough staff to meet the needs of the station.

Staff should also be appropriately trained and trained whenever new trends in

technology evolve. Usually, a sorting station consists of the key staff who perform the

synthesis and decay processes train crews, the station staff and the train controllers. It

is important to emphasize that manual work at the site of the sorting station is one of

the most dangerous works in the railway sector. Many wagons are moved through the

sorting station at different speeds during the splitting activities. Thus, excellent care

and experience are needed from those working at the sorting station. Therefore, an

attempt is made to reduce manual labor in the area as much as possible, and for this

purpose, automated systems are used (Banverket, 2009).

2.5.4 Maintenance

There are two development processes on the railroad:

1. The circulation process, which through the line-rolling interaction tends to

increase line errors and generally destabilize the whole system

2. The maintenance process, which attempts to reduce errors and restore the line

to the previous good condition.

2.6 PROBLEMS DURING OPERATION PROCEDURES INTO

THE MARSHALLING YARD

It is possible that problems can be encountered within a marshalling yard, having a

significant impact on the smooth and productive operation of the yard.

2.6.1 Switch engines

The problem regarding the switch engines mostly is encountered when the required

switch engine is working on another assignment while there is a significant number of

wagons that are waiting to be classified. In the case that a classification yard is large, it

22

is able to receive more trains. Therefore, a switch engine is enough to carry on the daily

operations of the yard. However, in smaller yards, switch engines can be assigned when

no wagons are being sorted. Line-hauls or engines which are called switch engines can

be used to pull short-haul trains. The engines that have as general-purpose to

disassemble and assemble trains are also able to provide energy to a short-haul train.

Switch engines are considered as an old approach because they do not include event

recorders. Therefore, more studies need to be conducted to determine their duties and

their annual activities (Lindhjem, 2008) (Todd, 2016).

2.6.2 Failure in the order of train wagons

Wagons is possible to present mechanical defects especially during check-in or check-

out inspections. Such as in case that a wagon has a defect, the outgoing train is delayed

until the wagon can be “set out”. Although these delays do not have huge impact on

the yard’s overall operating performance. But, a failure in the order of a wagons can

increase the travel time because the train has to be kept until repaired, resorted and

shipped to the assigned destination. (PWC, 2015).

2.6.3 Re-switching

Re-switching is a problem in the yard's operations as it can bound the traffic in the yard

but also bound a engine that could do more productive work. Otherwise, its impact on

the performance of the yard is not significant, especially in low-traffic yards, because

the activities are not very intense. Sometimes wagons need to be sorted more than once.

Therefore, there is a re-switching procedure. In some cases, a wagon may be sent in

the wrong direction. In such case, the wagon must be detached, return and to be re-

routed to the right track. This case of failure in the order of train’s wagons is another

example where re-switching is required since the wagon need to be removed, to be

repaired and to be sent for departure. Another case of re-switching occurs when the

classification tracks are less than the times of wagon need to be sorted. (TranSys, 2007).

Using emerging technologies that automate specific processes (some of them or all of

them) within marshalling yards can contribute in reduction of misroutes by processing

switching information faster and more accurately (Otto, 217).

23

2.6.4 Failures on the equipment

Mechanical breakdowns in equipment such as retarders, air compressors,

communication systems and more are a common occurrence. The performance of

equipment is a factor that may delay any operations within the yard, causing

congestions and delays in departing trains. The most common mechanical damage

recorded in the yards is the retarders. Retarder essentially control the speed at which

the wagons move, they move to the specified track, applying friction to the wagon

wheels. If a retarder fails and fails to operate correctly, there may be a collision of

wagons at an increased speed, causing additional space damage. An acceptable safe

coupling speed is usually four mph. To prevent such a failure, preventive maintenance

is carried out approximately once a week, and the procedure takes about a few hours.

This usually depends on each yard and the planning it undertakes to do (Jaehn, 2015).

2.6.5 Staff

Employees in marshalling yards, especially in those characterized by large and high

traffic and within walking distance of urban centres, may cause failure in the smooth

and proper operation of a sorting centre. Moreover, failures can be caused by human

error. However, practical and clear-cut solutions to such problems that require human

presence have not been proposed so far.

2.6.6 Extreme weather conditions

Rail operations at the marshalling yards may be disrupted or obstructed due to the

severe weather conditions that may prevail in the area. Such weather phenomena that

may disturb and possibly paralyze the smooth and effective operation processes inside

a yard may be flood, fog, snowstorm or frost. For example, a seasonal problem in

northern latitudes, such as Sweden, it snows during the winter and leaf fall during the

autumn season. In particular, within the marshalling yard, the tracks constructed close

to one another. Any attempt to push the snow off a path means that it will, unfortunately,

shift to the adjacent paths. In this situation, if we add the fact that the wagons are in the

yard, then, the removal of snow becomes even more complicated. In this case, before

the snow is removed, the wagons should be pulled out and temporarily stored

elsewhere. (Shift2Rail, D1.2 Description of automation optimization requirements and

capabilities of decision making process in marshalling yards and terminals, 2017)

24

It is worth pointing out another problem arising from the weather. In particular, the

rolling resistance of wagons is much higher at low temperatures. Specifically, the

viscosity from lubrication on the wagon bearings is quite high when the weather

temperatures are quite cold. Consequently, at the start of the wagon, the resistance to

the wagon start is much higher. Many times, in such cases, a slight back and forth

movement of the wagon is required so that the wagons can be moved more quickly.

Mainly, shallow temperatures can cause some delays in departing a train as it has to

deal with problems such as freezing some mechanical parts to classify the wagons in

the yard and thus may slow down some functions of the yard. In such cases, personnel

intervention is necessary to heat the frozen components. Because of the above, it is

evident that the prevailing weather conditions in an area to some extent affect the

activities within the yards, resulting in heavy traffic congestion and the time spent

inside exceeding the predetermined (Ludvigsen, 2014).

However, it is not only the low weather conditions that can affect the yard's activities.

Weather phenomena such as fog, heavy rainfall or snowfall are some of the phenomena

that act as an obstacle to the proper functioning of the yards. Low visibility, for

example, may make it difficult for operators to identify wagons, or to control the speed

at which a wagon moves. Snow and ice can also cause delays in the cleaning of the

yard, malfunction in the yard operations or even derailment. Heavy snowfall is an issue

as employees cannot walk comfortably and in the yard. Although some of these

problems can be addressed or eliminated as weather forecasts, tend to become more

valid nowadays. The use of new emerging technologies can automate many functions

so that human intervention is as small as possible. However, the weather is an unstable

factor which is an essential factor in the efficient functioning of the yards. (Ludvigsen,

2014).

2.6.7 Hazardous material handling

Special handling is required when wagons carry hazardous materials. Such materials

may be propane or chlorine, where they are transported in tank wagons or explosive

materials, where they are transported in specially equipped containers. In essence, these

wagons have a specific way of handling in the yards, and it is sometimes not allowed

25

the wagons with hazardous material to be classified over the hump with other wagons.

(Bagheri Morteza, 2010)

Indeed, in many cases, wagons carrying hazardous materials are classified in separate

sections apart from other wagons. This, of course, also depends on the yard in question,

the capacity available to accommodate such a dedicated section. Moving wagons to and

from these parts and putting them in their proper position on a train requires extra effort

from the staff. However, often the lack of dedicated staff or specialized personnel in

hazardous materials can reduce the efficiency of the yard (Rigas, 2002).

2.6.8 Expediting priority shipments

The operations of a yard may be disrupted for a short time due to other shipments which

are prioritized, so their expedition will be accelerated. Usually, this is considered

necessary when such a shipment involves hazardous materials or any other wagonloads

that are considered as vulnerable. However, such a procedure rarely causes substantial

problems in the proper functioning of a yard or is the cause of lost connections.

Nevertheless, it is one cause that may delay other missions. Thus, a unique design for

priority shipments is considered necessary to avoid any disruption to the operation of

the yard and to avoid any congestion or delay of other trains.

2.6.9 Derailments

One factor that can disrupt the overall functional operations of a yard is derailments.

Derailments also affect the safety not only of the products being transported but mainly

of the personnel working inside marshalling yards. However, because the speeds that

wagons develop in a yard are quite low, the derailments recorded are usually not very

severe. However, any damage that can be caused should be dealt with immediately, and

a considerable amount of time is needed.

Specifically, if derailment has occurred in a yard, then the procedure is as follows:

Initially, the wagons that are predetermined to follow the track where the derailment

has occurred are changing track. Then, the qualified personnel move to the rails with

the derailed wagon and try to clean up any possible partly due to the collision. Later,

repairing any damage to wagons and rails is performed. Such a process may take some

26

time as the wagon trails are close to each other and there is not much space between

them. So, pieces of the derailment may have been ostracized. Thus, the new design of

the yards must have a more vast space between the alternate paths. This makes it easier

to inspect the yard. While any maintenance process is possible without interruption and

congestion, it is worth stressing that poor maintenance of rail and equipment is a

significant cause of derailments. Thus, the correct application of wagon handling rules

and modern yard maintenance mechanisms can be factored in reducing such incidents

(Veritas, 2011).

2.7 NETWORK PROBLEMS RESULTING FROM

MARSALLING YARD OPERATIONS

This section deals with network problems that are directly related to the operations that

take place inside the marshalling yards. The reliability of the rail network is one way

of assessing it. Reliability generates benefits both for railway companies and for

customers who choose the railways as a means of transporting their goods. Indeed,

studies have shown the importance of marshalling yards and the effectiveness as one of

the main factors affecting the travel time of goods from the origin to the destination. It

is therefore particularly important to consider the impact of yard operations on the

railway network (Bohlin et al., 2013).

2.7.1 Train cancelations and late departures

Whether delaying a train departure or cancelling it from the yard are two problems that

are directly related to the performance of the overall rail network. These two problems

directly affect the reliability of the network as the switching times are much longer than

the projected time. Besides, there may be missing links from such an event. For

example, if a wagon loses its connection to one train, it has to wait for a new connection

to another train. Travel time is therefore increasing, and the likelihood of delay in

arriving in time is high. Therefore, the service is considered unreliable. It is worth

noting that lost connections affect reliability as long as delays of wagons are extensive.

While these delays are since the frequency of trains leaving the yard is low (Jaehn,

2015).

27

3. CASE STUDY OF MALMÖ MARSHALLING YARD -

GENERAL INFORMATION

3.1 GENERAL INFORMATION ABOUT MALMÖ’S

MARSHALLING YARD

Malmö’s marshalling yard has been used as a case study since it considered as the node

with the most departure delays in Sweden, as it is stated in the previous section. It is,

also, of high importance for the performance of the Swedish rail network, as it is the

first gateway yard in and out from Sweden.

Malmö Railway Station is located north of central parts of Malmö city adjacent to

Malmö Central Station and south of Malmö harbour. There is a passenger yard and a

marshalling yard. This happens because a car can be shunted several times but only is

reported in the statistics when it arrives or departs with a train. No loading or unloading

of goods occurs on the yard. There is no storage of wagons for a long time. Typically,

a freight wagon spends 10-15 hours on the yard. Longer times might occur on weekends

(Trafikverket, Nödlägesplan Malmö rangerbangård, 2014). In Figure 11, it is shown

the Malmö marshalling yard and Figure 12 presents an overview of the range of the

marshalling yard.

Figure 11 Malmö yard (Shift2Rail, Deliverable 3.1: Real time network management and

simulation of increasing speed for freight trains, 2018)

28

Figure 12: Overview of the range of the marshalling yard, blue scraping corresponds to geographical

demarcation level 1, yellow dotted line level 2. (Trafikverket, Riskanalys Malmö rangerbangård,

2013)

In Figure 13 , we show the total number of trains per day (black color) and only freight

trains (green color). As the number of trains is increased the thickness of the lines is

increased respectively. It is observed that the freight trains monopolize the north part

of Sweden. However, in the south part, the freight trains pass from the Hallsberg yard

connecting the Gothenburg and Malmö with the north. Moreover, passenger trains

monopolize the big cities of the country such as Malmö.

29

Figure 13 Total trains per day in Sweden (Lindfeldt, 2015)

In Figure 15 and Figure 15 we observed that the estimated medium of the delay

increased per 100km for passenger and freight trains respectively. The difference

between the two delays is due to the more significant spread of the distribution for

freight trains.

Figure 14 Estimated medium of the increased delay for freight trains [min/100km] (Lindfeldt, 2015)

30

Figure 15 Estimated medium of the increased delay for passenger trains [min/100km] (Lindfeldt,

2015)

3.2 TRAIN OPERATORS

The Swedish Transport Administration is the Infrastructure Manager of Malmö

marshalling yard and therefore manages the traffic through traffic control center in

Malmö. The yard operation is managed by the railway company, which is named Green

Cargo, which is also considered responsible for the shunting of wagons from other

companies. No other activities other than shunting and maintenance of the marshalling

yard are carried. However, directly adjacent to the marshalling yard (Trafikverket,

Nödlägesplan Malmö rangerbangård, 2014).

3.3 THE DESIGN AND FUNCTION OF THE MASHALLING

YARD

Malmö marshalling yard’s length is around 2,500m long and it consists of a combined

entrance/exit yard and a shunting yard. The arrival yard is extended in the north-

easterly and south-west direction and the classification yard in east-west direction. The

marshalling yard is the broadest because its length is around 200 meters, over shunting

group where there are 26 tracks in width.

31

There are several buildings, including the control tower, buildings for personnel, wagon

workshops and locomotives. However, it is only the control tower that lies within the

boundaries of the marshalling yard itself. Other buildings are used by other companies

such as SweMaint, EuroMaint and Jernhusen.

Figure 13: Location of the marshalling area, workshop and entrance area (Trafikverket, Riskanalys

Malmö rangerbangård, 2013).

At the south-eastern part of the marshalling yard is extended the Southern Main Line.

The marshalling yard ends in the west and then there is the Malmö passenger train park

that leads to Malmö Central Station and the City Tunnel.

At the marshalling yard, there are two types of tracks, the main and the side. Main tracks

are the tracks that have signals equipped with ATC (Automatic train control). Also, the

Main track is fully indicated as Traffic center Malmö (DLC), and it should be

mentioned that speeds of up to 200 km / h are achieved. The side tracks have easier

signalling or no signalling/indication of movements. On side tracks are called half-

sight speed due to the fact that speeds up to 30 km / h are achieved, which means that

movements should be able to stay on half the distance of sight (Trafikverket,

Nödlägesplan Malmö rangerbangård, 2014).

32

3.4 RAILWAY TRAFFIC

The number of wagons shunted on the Malmö’s marshalling yard is season-based and

can be affected by the general economic situation in the country. The last two years

about 160,000 wagons have been shunted each year at the marshalling yard. Every

month, between 10,000 and 15,000 wagons are shunted, which means a reduction

compared to 2000 when about 23,000 wagons were shunted every month. In addition

to these wagons, train movements can also be managed by other railway companies.

(Trafikverket, Riskanalys Malmö rangerbangård, 2013).

3.5 MARSHALLING

At the beginning, the wagons are pushed to a hump by the shunting locomotive. There,

a single wagon or a group of them are released. Then, the wagons are passing to one of

the three beam brakes. This function breaks the wagons down to about 5 km/hour. The

brake force is automatically occurred, and it is influenced by the weight of the wagon.

Then the wagon passes by several spiral brakes with lowers speed. At the tracks that

the wagons are switched, there are acceleration brakes that are able to lower the wagon

speed if it had increased during the last procedure.

There is an essential procedure in case of shunting dangerous goods. Because if a wagon

is loaded with Dangerous goods must keep a safety distance from the wagon in of it. A

new wagon may not be pushed until the wagon with dangerous goods passed the divide

switch to its destination track (Trafikverket, Riskanalys Malmö rangerbangård, 2013).

3.6 STAFF

The staff in marshalling yard is responsible for the shunting of wagons. The tower is

responsible for sorting the wagons on the yard, and it is mainly controlled by two

persons, a leader in planning the shorting and an operator. But during the weekend

shift, there is only one person that conducts both functions. Moreover, there is a Signal

33

Manager in the yard that manages the traffic in the yard area, and the location of the

Signal Manager is at Malmö Traffic Center.

Also, there are Shift Leaders in the Control tower every day, and they are responsible

for controlling and monitoring the shunting, such as in the case of an accident. If there

is no Shift Leader, there should be a Shunting Leader to do the tasks. Usually, there are

eight mean during the day and eleven men during the night. The Basic contractor is

responsible for the maintenance of the yard and uses two technicians who work in the

yard. It should be mentioned that at Malmo shunting yard, the maintenance is carried

out all day (day or night).

Additionally, Project Manager maintenance contractors may exist at the yard, but they

work directly under the Swedish Transport Administration. At the shunting yard, there

is also staff from the Train Operator such as train drivers (Trafikverket, Nödlägesplan

Malmö rangerbangård, 2014).

3.7 LIMITATION ON TRAINS LENGTH

Malmö’s marshalling yard features: Trafikverket, Regeringsuppdrag: Möjligheter att

köra längre och/eller tyngre godståg, 2015)

The Malmö’s marshalling yard has 39 tracks for different conditions.

Track’s length is under 650 meters.

Smaller tracks with 400 meters exist.

The arrival yard has 10 tracks and each track a length between 760 to 850

meters.

Nowadays, the Malmö’s marshalling yard can accept trains with length up to 750

meters but it is important to organize their arrival.

Limitations:

They can support 2-3 trains per days. These trains can either be shunted or pass

through Malmö marshalling yard.

34

In some cases, it is possible to depart or arrive long trains (more than 835

meters) to/from Germany and Denmark, but first, it is mandatory to measure the

yard. Specifically, at the arrival yard in Malmö, signal conversions of at least

two tracks are required on the arrival yard in order the trains to be adopted there.

(Trafikverket, Regeringsuppdrag: Möjligheter att köra längre och/eller tyngre

godståg, 2015). Theoretically, the rebuilding of the “Track 6” and the “Track 8”

allows trains to depart even if they are up to 835 meters.

These are the only restrictions regarding the trains that arrive and depart in Malmö’s

marshalling yard. However, another aspect that should be considered and has an impact

on the performance of Malmö’s marshaling yard is the robustness of the train traffic

system, which is not involved (Trafikverket, Regeringsuppdrag: Möjligheter att köra

längre och/eller tyngre godståg, 2015).

35

4. MALMÖ’S MARSHALLING YARD – DELAY ANALYSIS

4.1 STUDY VISIT AT MALMÖ’S MARSALLING YARD

For the completion of the thesis project, a study visit was carried out on Malmo’s yard

as the need for additional information and data was considered imperative at this point.

The visit took place on 24 April 2019. This study visit was organized by the supervisor

of this study, Dr Behzad Kordnejad. When we arrived at the yard, we met a group of

employees of “Green Cargo” (GreenCargo, 2019) in the control tower where we had

been invited. The group from KTH and the operational manager of Green Cargo had an

elaborated conversation about the operational procedures and current problem the

personnel faces that are related in some way with the delays might occur from the

moment the train arrives at the marshalling yard until leaves it. From the discussion

with the responsible person and the interference towards the other employees, there

have been some conclusions derived regarding the way of operation by Green Cargo.

The yard manager points out that Green Cargo operates marshalling yards by using the

BRAVO system (Thomas heydenreich, 2010). BRAVO is basically an IT application

for controlling and monitoring the operational procedures inside marshalling yards (as

shown in Figure 14). Essentially, all wagons need to be marshalled either they belong

to Green Cargo or to different companies. They must be imported into the Green Cargo

BRAVO wagon planning system, as they mentioned. This is because BRAVO provides

the data required for safe marshalling. Some of the main features of this particular

system are the transport bookings, the estimated departure and the arrival times for

reserved transports, the wagon booking on a train, the shipment and wagon information,

the planning of shunting activities, the client is informed for any delays and so on

(Shift2Rail, D2.1-Descriptionof automation/optimisation requirements and capabilities

of decision making process in Marshallingyards and Terminals, 2017). In the case that

the train is displayed in unscheduled time, either earlier or later than the specified one,

it should conduct a re-planning.

36

Figure 14: IT equipment of the operator in the Control Tower

A problem that the responsible person had indicated was that in Sweden with the current

followed operational tactics, the passenger trains have a priority in comparison with

slower freight trains. This principle imposes restrictions on freight trains such as the

difficulty to get time slots for freight trains resulting in the extension of travel time.

During the discussion, the issue of delays is further analyzed. More particularly,

statistics that sort of delay comes from the depot. The interviewee reports that although

most of the times the train is ready for departure, it is not given any command in order

the train to exit the yard. The main reason, as she mentions, is the reduced railway

capacity. A research study conducted by (Lindfeldt, 2015) deals with railways capacity

aiming to analyze the symptoms and the underlying behaviour of railway congestion.

They proposed different methodologies in order to analyze the capacity. One of the

proposed methods analyzes how different factors influence the availability of capacity

and train delays. Another approach analyzes the characteristics of double=track

operation with the result of an in-depth understanding of the mechanisms of railway

operation on tracks with double lines.

37

Another issue that came up along with the discussion regarding delay issue is the

foreign trains coming from abroad. The person in charge reported that most of the times

these trains arrived at the yard, not at the scheduled time. Especially nowadays, there is

a kind of issues related to maintenance in Denmark’s railways as was pointed out by

the responsible person. Another issue that came up was a problematic situation

regarding foreign trains because these trains tend to arrive during the night when there

is not the ability to take care of the incoming trains.

During the conversation, we tried to understand the configuration of Malmö’s yard. The

marshalling yard of Malmö constitutes of 39 tracks where 15 of them are full-length

tracks, which means can be served full-length trains in the Swedish network which can

be roughly 600 meters. The short length tracks are used for local trains distributing and

picking up. Approximately 600 to 800 wagons it is expected to be shunted every day.

However, arrival and departure tracks are shaped each day differently, and as

mentioned by the responsible person is mainly based on the size of the trains. The

departing and arriving tracks in the marshalling yard are ten, but there is no division

between the arrival and departure yards. Specifically, they use the same tracks for both

purposes. Furthermore, they noted that the tracks from the west side are exclusively

connected to the port. In Figure 15, it is shown the track for foreign tracks which is

located on the left side of the yard. In Figure 16, it is shown the hump in the marshalling

yard of Malmö.

Figure 15: Track for foreign freight trains (left side)

38

Figure 16: The hump in the marshalling yard of Malmö

If the locomotives are considered, there is not a problem regarding their, at least not so

far. It should be highlighted that in cases of harsh winter, it is possible to experience

problems regarding the lack of locomotives. There is a similar tool such as BRAVO,

which is referred exclusively to locomotives, it is named “PLATÅ”. “PLATÅ” is a

software system and is used for the operational schedule of locomotives and train

drivers. This system connects the locomotives with wagons, but no information for the

operational procedure was given from the staff. Moreover, Green Cargo has an IT

system called “LOOP” which is used for the simulation, the optimization and the

tactical schedule of locomotives (IP5ARC, 2017).Arrival inspection and brake test are

important activities inside a marshalling yard. Inspection is implemented on the wagons

for mechanical damage, allowing them to be transported to a repair facility when they

are sorted. While the braking system is engaged during the process of separating

wagons, but before their transition, the brakes must be released in each wagon

separately by a mechanic officer, either manually as happened in the past or

automatically. (Baugher, 2015). The information received during this study visit was

that both activities usually takes 30 to 45 minutes the maximum, where for each train a

person from the staff undertakes to inspect it. At the same time, there may be up to 2

staff members who do the inspection procedure and another one who is responsible for

hump. It is mandatory to complete their work an hour the departure of the train.

39

Another problem regarding delays in the marshalling yard of Malmö, according to the

operation manager is that occasionally they face lack of available tracks in comparison

with the number of booked destinations which are more. Consequently, many wagons

cannot be distributed properly, especially on the weekends, because the tracks are full.

Another different issue is the dangerous goods. Their processes are far more time-

consuming than a conventional train that carries no dangerous goods. According to

Green Cargo’s employee, the train should stop on the hump when it arrives. Then, a

person from the staff let a wagon to pull down in the hump in order to stop smoothly.

The next step is to ensure that the wagon is stable at staffed location or siding. When it

is confirmed that the wagon is stable, then the next wagon follows the same procedure.

After the dispatching of dangerous goods, they are checking out the trains to detect if

there are any defects. It was mentioned that the allowed number of wagons which carry

dangerous goods is up to 15 in each train for this yard.

Even though employees admit that having arrival and departure tracks separated from

each other would optimize the operations in the marshalling yard, however, they are

not going to change this procedure since there is no time to remodel the space because

this is mainly the responsibility of the Swedish Transport Administration.

According to the person in charge of the most problematic sector among all in the

marshalling yard of Malmö (arrival/departure yard, classification bowl) is the arrival

yard in most of the cases. Even though the procedures within the classification bowl

are not characterized by long delays and this phenomenon is not frequently

encountered, the late arrival affects negatively the processes carried out inside

classification bowl. As, the mentioned, in such cases, bookings, need to be changed.

However, the re-booking depends on how late the train arrives at the marshalling yard.

In case of train cancellation, they usually assemble other wagons that are already

standing in the yard.

Another issue that is equally important and affects the operational processes inside the

yard is the extreme weather conditions prevailing mainly during the wintertime in

Sweden when the thermometer shows temperature below zero. These conditions affect

40

mainly the switches and the brake system. The infrastructure is old, and its maintenance

is considered substandard as the switches or the brake system fail to function properly.

In addition to the issue that prevents the proper operation of Malmö’s yard is the fact

that in many occasions is difficult to identify the type of wagon. This contributes to the

difficulty of identifying the following track.

Regarding the braking system, this works automatically. However, it is not scheduled

to automize any other procedure for the moment. The IT equipment was planned to be

replaced with a new one soon, and the responsibility is upon the Swedish Transport

Administration. The yard has a back-up system that generates electricity in the case of

a power interruption. Based on the staff shortages and this factor is not affecting the

operational procedures.

In Figure 17 and in Figure 18, it is shown the double-sided beam brake.

Figure 17: Double sided beam brake - hump beam brake

41

Figure 18: Double sided beam brake - hump beam brake

Another issue that should be mentioned in this thesis is that trains in Sweden can depart

earlier. This practice was also confirmed during our discussion with the person in

charge. They mentioned that it is possible to allow trains that are already finished to

depart for their intended destination. The author of (Khoshniyat, 2019) argues that

passenger trains are not affected in a negative way, if the freight trains have a priority

and depart ahead of schedule time. However, they don’t know to what extent the early

departure of passenger trains may affect the freight trains.

It is not usual to wait for delayed wagons since there are other clients on the train who

have paid in order to be delivered on time. In this case, the late wagons try to be

rebooked to another block of wagons. Sometimes, exceptions may occur, such as in the

case of the Volvo company. Volvo is considered a regular customer with a large volume

of goods to be transported.

Finally, when a train is about to depart sometimes may be blocked by another train that

arrives on the same track. In most of these cases, there is a delay on the trains that

arrives. They do not use to schedule two trains on the same track. Instead of that,

42

grouped trains are scheduled. Otherwise, there is a need for two tracks to make a set of

different destination trains, since not all the tracks have the same length. The yard does

not have the capability to keep standing wagon for a long time because of the shortage

of tracks. Nevertheless, the interviewee indicates that this phenomenon happens only

during weekends, and the maximum stay is up to 2 days. And the maximum length of

the trains that can reach up to 670 meters while abroad is up to 700m.

4.2 MODEL STRUCTURE DESCRIPTION

The transit time of a freight wagon is a key parameter for the efficiency of a yard. The

transit time of a freight wagon can be calculated as the time from the arrival of the

wagon assembling to a train until the departure of that wagon assembled to a different

train at that time. In particular, the sum of the time required for the development of each

activity in the yard is related to the transit time of a wagon. It is worth mentioning that

the time required for each activity consists of waiting time and operational time. (Ricci,

2017).

In order to mode the processing times, we should analyze all the tasks which are

relevant to marshalling operations of cargo units. Initially, we need to determine and

the main stages, such as the waiting the operational stages. In order to create the

simulation model, a general structure was followed, and it is shown in the Figure 19.

43

Figure 19 General structure of the simulation model (Khoshniyat, 2019) is modified and includes all

the processing stages

More specifically, in the model the train arrival is reproduced and its related check-in

operations (Khoshniyat F. , 2012):

a) Reserve;

b) Driving;

c) Securing cars and uncoupling them from locomotive;

d) Checking and preparation (1 min per car);

e) Coupling to the shunting locomotive;

f) Pulling, releasing brakes, waiting for signals;

g) Pushing cars over to the hump;

h) Rolling over hump;

Two different assumptions were made regarding the train movement in the yard for the

arrived trains in Malmo’s yard:

1) Only two tracks out of the ten are used when a train arrives. These are Track 9

and Track 10.

44

2) The route planning that is applied is to forward the train at the track with the less

queue (less busy), when it arrives.

The operational tasks of the wagons when enter the classification yard reproduced as

well (Khoshniyat F. , 2012):

a) Coupling cars and brakes;

b) Time for filling the brake system with air;

c) Testing the brake system;

d) Refilling the brake systems after the test;

e) Brake test, hitting the brakes, controlling each car;

f) Releasing brakes;

g) Controlling that all brakes have been released;

h) Release buffer stops;

i) Activate brakes;

j) Time for driving the locomotive to the cars and coupling it;

k) Releasing brakes;

l) Simple brake test;

m) Time for departure including path reservation

n) Time for activating buffer stops, relays, reaction time

However, the above processes are grouped into two categories in order to have a better

understanding of the model. Specifically, the categorization for the first group is related

to the tasks from “a to g” from the above list and the second categorization relates to

the operational tasks from “h to n” based on the list above. The only assumption that

was made for the wagons’ movement when they are in the classification bowl was the

following: “The wagon distribution is made randomly”.

At the model, each process takes place 26 times (i.e. 26 tracks where the shunting is

applied). It was considered preferable to group some of the activities that are taking

place in the classification yard. This happened mainly for practical reasons. We

considered that there are 26 tracks, in which the sorting process takes place, and in each

track, the operation tasks carried out are 14 in total, according to the previous study

45

used. (Fahimeh, 2012). The representation of all these tasks for all 26 lines causes

graphic confusion.

Finally, follow the processes before departing from the marshalling yard (Khoshniyat

F. , 2012):

a) Driving;

b) Uncoupling from the shunting locomotive;

c) Driving the shunting locomotive away;

d) Driving the line locomotive to cars;

e) Coupling to the line locomotive;

f) Charging the brake pressure;

g) Simple brake tests;

h) Waiting for the signal;

i) Departing;

In this thesis, we have made three assumptions:

1) In the model, eight tracks are used when a train is departing. These are tracks 1

to 8, no matter what that the same yard may be used for arriving. But, in real

cases, all ten tracks are used for departing.

2) In the model, we plan the root with the restriction to forward the train at the track

with less queue, in case of a train departure.

3) In case of train departure, it can depart on if there is no queue ahead.

For the purpose of this thesis, a simulation model was created by Planimate software

(Planimate, 2019), which is developed by InterDynamics. More specifically, Planimate

is able to build simulation models of discrete events. It is also quite flexible and

appropriate for simulating complex systems using large amounts of data and sub-

processes, thereby ensuring easier monitoring of the system’s evolution. Essentially,

this program depicts the simulation model graphically using several objects to represent

the arrival yard, the classification bowl, the exit yard, the operational tasks (e.g. check-

46

in inspection) and so on. The “Items” also are a significant part of the model since they

are transferred from an object to another one. They could change their properties

sometimes when they are passing through an object. In our case study, trains and

wagons are the items. An advantage of this tool is that the University students can use

it without any cost. On the other side, an important disadvantage is that they do not

provide any tutorial in order to help the user to understand how to use it apart from

some example models inside the program and a few information about the elements of

the simulation tool and its properties.

It is worth mentioning that the time measurements which were used on the simulation

model have been taken by another research on marshalling yards. The paper of

(Khoshniyat F. , 2012) hat deals with the Hallsberg’s marshalling yard, which is quite

like the design structure of Malmo’s marshalling yard. Since it was not possible to get

any real-time measurements from Malmo’s yard for this case study, it was decided to

use previous data from a marshalling yard alike to Malmo’s. The previous data and the

measurements are presented in the Appendix section.

The infrastructure of the simulation model includes the following basic elements:

Objects: They are fixed entities within the system; they do not move but remain

constant. Besides, they can change the properties of the entities running through

them when the simulation model runs or maintaining those properties for a

specific time period.

Items: They are dynamic entities within the system and can enter in it, they can

move from object to object by changing properties, and they can leave from the

system. In our case, these are the trains and wagons.

Some prerequisites have been set. The system status must conform to these

requirements which are active.

47

The Items can move from one object of the network to another using the Paths during

the simulation. The Path symbolizes a logical progression of events between two or

more Objects that determines the evolution of the system. Thus, first of all, it is

necessary to identify the Objects for the model design. Then, we can create the Paths

that allow objects to move from one object to another, creating a series of steps that are

necessary for the simulation of the system evolution. Also, a set of Paths through which

Objects can move is called Flow. Note that in the model, the Portals are representing a

function performed within the yard. The typical Flow that was followed in a

marshalling yard and applied in the simulation is shown in Figure 23.

48

ARRIVING TRAIN

CKECK LOCOMOTIVE AND

WAGONS

CHANGE LOVOMOTIVE

ENTRY IN OPERATIVE TRACK

UNCOUPLING SHUNTING

LOCOMOTIVE

START OPERATIONAL TASKS

(ex. BRAKE TESTS)

TRAIN CHECK

COUPLING LOCOMOTIVE

EXIT TRAIN

Figure 20: Schematic representation of the flow in a marshalling yard.

49

4.2.1 Sub-systems of the model

(1) Train arrives at the arrival yard (Arrival sub-system)

Initially, the train waits for the signal since it has arrived at the arrival yard. Then the

train goes to the assigned track when it receives the appropriate signal with “green”

colour. The train is parked in the arrival track, the wagons are disconnected from the

train locomotive, and they are connected to the shunting locomotive. After it comes to

the brake check. Later, when the signal is green, the wagons are scrolled over the hump,

and they are forwarded to the assigned track in the classification bowl as we can observe

in Figure 21 and Figure 22

Figure 21: Arrival sub-system

50

Figure 22: Arrival sub-system

(2) Activities in the classification bowl (Classification sub-system)

Before leaving a track, specific tasks should be performed on the wagons inside the

classification bowl. If a track is engaged, it needs a short time to declare that it is not in

use anymore. Also, in Figure 23 is shown, the sorting procedures such as to release

brakes consists of several sub-procedures.

Figure 23: Classification sub-system

51

(3) Train departures from the arrival/departure yard (Departure sub-system)

The train leaves the yard and goes on the assigned departure track only when it is set,

and the wagons of it are assembled. The departure yard performs a variety of tasks to

prepare the train for departure. Examples of such tasks are the disconnection of the

shunting locomotive from the group of wagons and the connection to the departing

locomotive. In Figure 24 we show how the tests on the braking system are carried out

as well as some other activities.

Figure 24: Departure sub-system

52

4.3 SIMULATION RESULTS

Three scenarios were performed on the model that was created.

4.3.1 Scenario: No automation

This scenario is considered without any usage of automation throughout the operations

inside the marshalling yard of Malmö. The time was used for each task has been taken

from time measurements on Hallsberg’s Marshalling yard existing in another study

(Khoshniyat, 2019). While the model was running, the total time of each train entering

the arrival yard until exiting the marshalling yard was recorded. The Figure 25 shows

that the time inside the yard tends to be increased for each train which is entering in it.

Figure 25: Scenario 1 – Trend performing based on arrival times

111113115117119114

120120122129125123125127129

121

143145147149155

150149

0

20

40

60

80

100

120

140

160

180

1:51

1:53

1:55

1:57

1:59

1:54

2:00

2:00

2:02

2:09

2:05

2:13

2:15

2:17

2:19

2:21

2:23

2:25

2:27

2:29

2:35

2:30

1:29

DEL

AY ARRIVAL TIMES

53

4.3.2 Scenario: With Automation

In this scenario, automation is applied in the case of the arrival yard, more specifically

during the check-in procedure. Regarding the automation, it could be any kind of

emerging technology such as cameras and scanner in order the process of identification

and preparation for the assigned track to be accelerated. The results are presented below

in Figure 26.

Figure 26: Comparison between Scenario 1 (No automation) and Scenario 2 (With automation)

More particular, the graph in Figure 26 shows the difference in the time spent in

Malmo’s marshalling yard without and with automation. More than two hours are

needed for the marshalling yard procedures for a train on average.

A high time-consuming procedure is the Check-In in the arrival yard. With the usage

of new technologies and automation, the Check-In time can be reduced in 75 minutes.

There will be a reduction of 41.86%, which is important.

4.3.3 Scenario: Automation of additional procedures

0

20

40

60

80

100

120

140129

75

Tota

l Tim

e (m

inu

tes)

Usage of automation

Scenario 2

With no automation

With automation in Arrival Yard

54

This scenario deals with the automation of additional procedures not only at the arrival

yard but also before the train leaves the yard, at the “departure” yard. In this case, we

observed a different case. In this scenario, there is a small reduction of time (only 7

minutes shorter) in comparison with the Second Scenario.

Moreover, the time of a train in a marshalling yard has been reduced by 47.29%

compared to the first scenario while compared to the second by 9.33%. It was observed

that the third scenario is essentially the best, as it is shown in Figure 27.

Figure 27: Comparison between Scenario 1 and Scenario 3 (AY: Arrival Yard, DY: Departure Yard)

0

20

40

60

80

100

120

140

Scenario 2

129

68

Tota

l tim

e (m

inu

es)

Usage of automation

Scenario 3

With no automation

With automation AY & DY

55

5. CONCLUSION

Malmö΄s marshalling yard has features that make it a special case that is worth studying.

Some of them are listed below:

The location of the marshalling yard is important and challenging at the same

time. It is the main node for wagon load freight, where freight to and from Europe

is assembled to trains. And in line with forecasts by the people in the yard’s

operation management, the demand for freight services is on the rise in the

coming years.

However, many clients try to avoid passing their goods through this yard because

there could exist a confusion in the yard related to the delay. In many cases, the

delay exceeds the estimated time, and this results in additional cost. Additionally,

the policy of Green Cargo gives priority, mainly to clients that collaborate with,

such as in the case of the Volvo company. Therefore, private companies operating

in the field of rail freight transport are not being in particularly favorable

conditions.

The structure of the Malmö’s yard does not represent the typical layout of a

marshalling yard, where arrival yard, classification bowl and departure yards are

observed. In the case of Malmo’s marshalling yard, the arrival and the departure

of a freight train are performed from the same yard. Thus, such a structure may

have an adverse effect on the usual operation of the marshalling yard reducing

the capacity utilization of the yard.

Another important fact that the marshalling yard is alleged relates to the city

planners because they are trying to relocate the yard to another area towards a

suburban area outside the city center of Malmö. As it is known, the yard was built

adjacent to the passenger train station and the city center. However, urban

planners insist on changing land and use the current location of the yard. This

phenomenon, according to (Dablanc Laetitia, 2010) that logistics facilities are

relocated and concentrated to suburban areas outside the city center is called

“Logistics Sprawl”. However, such action is particularly costly for the Swedish

Transport Administration.

56

Summarizing, the late arrivals of incoming trains is the key reason for the delays of

departing trains. However, it is not the only one. To some extent, the delays are due to

the failure of the rail network. For instance, passenger trains often have priority over

slower freight trains. This tactic imposes problems on freight trains such as the

difficulty to get time slots that result in the extension of travel time.

Another example is the case of foreign trains that are coming from abroad. Because in

some cases, they arrived at the yard not at the scheduled time due to maintenance issues

of the railways.

In addition to network failure, there are other factors that adversely affect internal

processes such as the extreme weather conditions mainly during the wintertime in

Sweden. These conditions affect mainly the switches and the brake system as it is

mentioned previously.

Also, there are internal factors that increase the total time of a train inside a

marshalling yard, such as reduced railway capacity and the lack of available tracks in

comparison with the number of booked destinations. A possible solution to smooth out

any delayed arrival of a train or delayed internal process is the creation of one buffer

time. Based on our knowledge, so far it is not applied in the Malmo’s marshalling yard.

Basically, the buffer time is an extra time added to keep a project on track. In the

planning phase, this margin is important to handle any risk that could be occurred.

Implementing a buffer time for the internal processes the operational managers could

be able to deal with unforeseen situations without the need to make major changes on

the coordination of the operational undertaking.

5.1 DISCUSSION

Even if the problem of malfunctioning in the rail network still exists, measures for

protection can be considered to smooth out any delay. IT Systems, like BRAVO,

(Heydenreich, 2010) can be upgraded in order to be used not only to control and monitor

the internal procedures. An upgrade at the system can provide to the operational

57

managers constant updating of the location of each train and calculate the possibility of

arrival train delay at the yard. In this case, there will be time to reschedule the

procedures in the yard according to the specific conditions. It is also likely that in such

a case, the tactics regarding a possible delay should be redefined since there is

information regarding the arrival time through the system. It would be very interesting

to see in the future what would be the impact of such an implication on the punctuality

of freight trains in marshalling yards and how it will be managed the inside operations.

In addition, any application of automated processes within the marshalling yard, it will

facilitate and speed up the internal processes as demonstrated by the simulation model.

The benefits of applying new technologies, as it was observed from the simulation

scenarios, it will be beneficial because they could decrease significantly the time to

succeed faster arrival/ departure procedures. And at the same time, there will be

optimization on operational management.

5.1.1 LIMITATIONS

Although the study was conducted over a good time period, unfortunately, some data

regarding the operations within this yard were not able to be collected. This could be

particularly helpful in this study because specific measurements were required. For

instance, the time measurement of each activity indicates how long each activity lasted,

including the amount of time it takes the wagon to be transported from one activity to

another within the marshalling yard. Thus, time measurements from another study

carried out (Khoshniyat F. , 2012), in a similar type of yard in order to have more

realistic results.

Regarding the literature review in this thesis, it was conducted after a respected period

of continuous searching as there were not many similar studies, and often the collected

data was old. So, it was necessary for the writer of this thesis to search for new studies.

Moreover, the Swedish language was a barrier since most of the documentation was

written in the Swedish language.

58

5.3 FUTURE RESEARCH

In addition, this study was confined to a single Swedish shunting yard, which is

particularly problematic. A similar study could be realized for other problematic yards

in Sweden and internationally with a target to identify the main causes of delay in the

marshalling yards and then to compare our results with these.

The use of new emerging technologies to optimize the operations in the marshalling

yards gives scientists the opportunity for future studies in this direction. For instance,

it will be important to make further research on the overall performance of a yard after

implementing new technologies and whether the application of new technologies would

have a positive impact on the overall rail network of a region or country. Therefore, it

is observed that there are many issues that need to be studied regarding the application

of new technologies in the yards.

59

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65

APPENDIX

Time measurements of several tasks in marshalling yard of Hallsberg (Shift2Rail,

D2.1-Descriptionof automation/optimisation requirements and capabilities of

decision making process in Marshallingyards and Terminals, 2017) (Khoshniyat

F. , 2012)

Figure 28 Approximate time to prepare a train for shunting

Figure 29 Dedicated time to different operational tasks

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Figure 30 Dedicated time to several tasks before departing

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