The document provides a detailed overview of railroad turnouts, including their definitions, types, components, and working principles. It explains the necessity of turnouts for directing train movement and describes various switch components such as points, frogs, and guard rails, along with types of switches. Furthermore, it covers track junctions and crossings, including their requirements and classifications, to facilitate train operations on different tracks.

1. Aman Bathla
(A.P.)

2. Review of Syllabus
Unit – II
Part - I

3. Turnout: Definition
 Arrangements by which different routes either parallel or
diverging are connected & afford the means for trains to
move from one route to another.
Sometimes turnouts, cross-overs are also used in place of
points & crossing.

4. Turnout: Necessity
 The direction of movement & the diversion of the vehicles to
the another track are controlled automatically by wheel
flanges rather than the driver as in case of roads.
 Provide flexibility of movement y connecting one line to
another.
 Impose restrictions over turnouts to retard the movement.

5. Turnout: Types
 The simplest combination of points & crossings which
enables one track to take off from another track.
Depending upon the direction of movements of trains from
main track; turnout are classified as
Left hand turnout
Right hand turnout

6. Left-hand Turnouts
The diversion in which train from the main track is diverted
to the left of the main route in the facing direction.

7. Right-hand Turnouts
The diversion in which train from the main track is diverted
to the right of the main route in the facing direction.

8. Turnout: Working Principle
 Turnout works with the combination of Points & crossings.
This consist of mainly a pair of points or switches, Four Lead
Rails, two check Rails & crossing.
Rail track A divides into two: track B (the straight track) and track C
(the diverging track).
the green line represents direction of travel only, the black lines
represent fixed portions of track, and the red lines depict the moving
components

9. Turnouts: Components

10. Turnout Component: Switch
The pair of linked tapering rails, known as points (switch
rails or point blades), lying between the diverging outer rails
(the stock rails).

11. Switch Component: Points
The points (switch rails or point blades) are the movable rails
which guide the wheels towards either the straight or the
diverging track.
They are tapered on most switches, but on stub switches they
have square ends.

12. Switch Component: Frog
 The crossing point of two rails.
 Assembled out of several appropriately cut and bent pieces
of rail or can be a single casting of manganese steel.
also known as the common crossing (or V-rail in Australian
terminology).

13. Switch Component: Guard rail
 A short piece of rail placed alongside the main (stock) rail
opposite the frog.
 Ensure that the wheels follow the appropriate flange way
through the frog and that the train does not derail.
Generally, there are two of these for each frog, one by each
outer rail. Guard rails are not required with a "self-guarding
cast manganese" frog, as the raised parts of the casting serve
the same purpose.

14. Other Switch Components
 Stock Rails (The main rails of the track)
 Tongue Rails (lie between two stock rails & are tapered to a
point)
 Heel Blocks (blocks inserted between the heel of the
tongue rail & stock rail)
 Distance Block (block to provide distance between running
rail & check rail)
 Stretcher Bar (bar through which the tongue rails are
connected together)

15. Important terms in Switches
 Heel Clearance/ Divergence
Distance between the running faces of stock rail & tongue rail
 Switch Angle
Angle between running faces of the stock rail & tongue rail
 Throw of Switch
Distance through which the toe of the tongue rail moves
sideway

16. Types of switches
1) Stub switch (No separate tongue rail is provided)
2) Split switch (Tongue Rail is combined with the stock rail)

17. Split switch: Types
1) Loose-heel type
 2 Front bolts are kept loose
 Are not favored
2) Fixed-heel type
 Tongue & stock rail kept in position by means of heel or
distance block
 Use is limited only long switches

18. Crossing & its requirements
Device to permit vehicles moving along one track to cross the
another track.
Requirements
 A side plate should be provided for connecting the point &
splice rails. ( Turned bolts should be used for this
connection)
 The foot-flanges of the wing rail should be riveted to the
plate.
 Alloy steel for light traffic & high manganese steel should be
used on crossing
 Crossing should be rigid.

19. Crossing: Types
1) Acute Crossings or V crossing
Acute angle of intersection
2) Obtuse Crossings or diamond crossing
Obtuse angle of intersection
3) Square Crossings
Tracks are at right angles

20. Important terms in Crossings
 Theoretical nose of crossing (T.N.C.)
Sharp imaginary point where the two gauge faces would meet
 Actual nose of crossing (A.N.C.)
Point rail is never manufactured to a well defined sharp point
as it would break off under the action of moving traffic
A blunt nose is provided for the point rail.

21. Track Junction
Combinations of points and crossings, with curves &
straights to transfer trains from one track to another
Important track junctions
 Three throw switch
 Diamond crossing
 Cross over
 Single & double slip
 Triangle

22. Three throw Switch
Two turnouts take off from the same point of a main
line track. A three-throw switch can have contrary
flexure (either side of main track) or similar flexure
(one side of main track)
Contrary Flexture Similar Flexture

23. Diamond Crossing
Straight or curved tracks of same of different gauges
cross each other at angle less than 90 degree

24. Cross-overs
Connecting line between two adjacent parallel or
diverging tracks

25. Single slip
Tracks can be changed from one direction only

26. Double Slip
Tracks can be changed from both directions

27. Scissor Cross-overs
Combination of one cross-over over the other cross-
over in the opposite direction.

28. Turntable
Required for changing the direction of engines

29. Triangle
Required for changing the direction of engines

31. Do you have Any Question?