Turnouts • It is the simplest combination of points and crossings.

• It enables one track to take off from another track.

• it is an arrangement of points and crossings with lead rails by which rolling stock may be diverted from one track to another when moving in facing direction.

Components of a turnout• A pair of points or switches• A pair of stock rails• Check rails• Lead rails• Stretcher bars• Crossings or ‘V’ piece• Wing rails

Switch points• the pair of tapered moveable rails known as the switch points (switch rails or point blades)

• A pair of stock rails

Check rails• A guard rail (check rail) is a short piece of rail placed alongside the main (stock) rail opposite the frog.

• On a fixed railway crossing, the wheels need only drift by a small angle, say 1 in 20, before the vehicle may start to go in the wrong direction at the V of a V-crossing. This problem can limit the maximum speed of vehicles using the crossing.

Types of switches• Stub switch:• In this type, no separate tongue rail is provided. Instead, some portion of the track is moved from one side to the another.

• However, stub switches are not used in Indian railways.

• Split switches:A track structure used to divert rolling stock from one railroad track to another and consisting essentially of two movable point rails with necessary fixtures– Loose heel type:The switch or tongue rail finishes at the heel of the switch. It enables a free end of the tongue.

– Fixed heel type:The tongue rail does not end at the heel of the switch but extends further. The tongue rail id rigidly connected to stock rail at the heel.

Components of a switch• A pair of stock rails AB and CD• A pair of tongue rails PQ and RS- switch rails

• A pair of heel blocks• A number of slide chairs to support tongue rail and to facilitate its movement towards or away from stock rail.

• One or more stretcher bars to connect both tongue rails

• A gauge tie plate to ensure correct angle.