3. Turnout
• In case of roads – vehicles move in any
direction
• Trains - not possible at will to change the
direction
• Change is made possible with the provision of
turnouts
• Consists of points and crossings.
• Information sent to loco pilot using signals.
4. Turnout - Definition
• Simple arrangement of points and crossings by
the manipulation of which the train from one
track may be diverted to the another track or
branch line or to siding is known as turnout.
• 2 tracks either merge or diverge, or 2 tracks
parallel to each other but are still connected
to each other- This connection helps in
changing the direction of trains.
• for this points and crossings are used.
5. Turnouts
• The combination of lead rails with curved rails
(and fastenings) helps in diverting rolling stock
from one track to another track.
• Rails depending on curvature
– Lead rails are straight
– Curved rails have curvature
• Turnouts are also provided in yards and
sidings
6.
7. Turnouts and Problems
• Some problems exist
• Weakest points on the track due to joints and
fastenings. Safety becomes main concern in
design
• Retards the movement of the trains
8. Types of Turnouts
• Depending on direction of movement of trains
from main tracks
– Left hand turnout
– Right hand turnout
10. Component Parts of a Turnout
1. A pair of tongue rails
2. A pair of stock rails
3. Two check rails
4. Four lead rails
5. A Vee crossing
6. Slide chairs
7. Stretcher bar
8. A pair of heel blocks
9. Switch tie plate or gauge
10. Parts for operating points-
Rods, cranks, levers etc
11. Locking system which
includes locking box, lock
bar, plunger bar etc
11. • Facing direction:
– Standing at switch and looking towards crossing
• Trailing direction:
– Standing at crossing and looking towards switches
• Points:
– A pair of tongue rails with stock rails
– Train diverting from the main track will negotiate
these points first.
12. • Tongue Rail:
– It is a tapered movable rail, made of high-carbon
or -manganese steel to withstand wear.
– At its thicker end, it is attached to a running rail.
– A tongue rail is also called a switch rail.
• Stock Rail:
– It is the running rail against which a tongue rail
operates.
13. • Switch angle:
– angle between the gauge face of the stock rail and
tongue rail at the theoretical toe of switch.
• Throw of switch:
– Distance by which the tongue rail moves laterally
at the toe of switch
14. • Crossing:
– A crossing is a device introduced at the junction
where two rails cross each other to permit the
wheel flange of a railway vehicle to pass from one
track to another.
15.
16. Switches - Components
• A set of points or switches consists of the
following main constituents
– A pair of stock rails
– A pair of tongue rails
• also known as switch rails, made of medium-
manganese steel to withstand wear. The tongue rails
are machined to a very thin section to obtain a snug fit
with the stock rail. The tapered end of the tongue rail is
called the toe and the thicker end is called the heel.
17. Switches
– A pair of heel blocks which hold the heel of the
tongue rails is held at the standard clearance or
distance from the stock rails.
– A number of slide chairs to support the tongue rail
and enable its movement towards or away from the
stock rail.
– Two or more stretcher bars connecting both the
tongue rails close to the toe, for the purpose of
holding them at a fixed distance from each other
– A gauge tie plate to fix gauges and ensure correct
gauge at the points.
18. Types of Switches
• Two types
– Stud switch
• no separate tongue rail is provided and some portion of
the track is moved from one side to the other side
– Split switch
• These consist of a pair of stock rails and a pair of
tongue rails
• These are 2 types
– loose heel type
– Fixed heel type
19. • Loose heel type:
– In this type of split switch, the switch or tongue
rail finishes at the heel of the switch to enable
movement of the free end of the tongue rail.
– The fish plates holding the tongue rail may be
straight or slightly bent.
– The tongue rail is fastened to the stock rail with
the help of a fishing fit block and four bolts.
20. – The fish bolts in the lead rail are tightened while
those in the tongue rail are kept loose or snug to
allow free movement of the tongue
– As the discontinuity of the track at the heel is a
weakness in the structure, the use of these
switches is not preferred.
21. • Fixed heel type:
– In this type of split switch, the tongue rail does
not end at the heel of the switch but extends
further and is rigidly connected.
– The movement at the toe of the switch is made
possible on account of the flexibility of the tongue
rail.
22. Based on Toe of Switches
• Undercut switch
– The foot of the stock rail is planed to accommodate the
tongue rail
• Straight cut switch
– Tongue rail is cut straight along the stock rail to increase
thickness at toe.
• Over riding switch
– Stock rail occupies the full section and the tongue rail is
planed to a 6mm thick edge which overrides the foot of
stock rail
– Switch rail is kept 6mm higher than the stock rail from the
heel to the point towards the toe where planning starts
– Eliminates the possibility of splitting which might be caused
by the movement of false flange in the trailing direction
23. – Stock rail is uncut, hence more stronger
– manufacturing work is confined only to tongue
rail, which is very economical
– Tongue rail supported by stock rail, hence
combined strength of rails between sleepers is
greater than that of tongue rail alone in the case
of undercut switch.
– These overriding switches are standardized and
used in IR.
24. Crossings
• A crossing or frog is a device introduced at the
point where two gauge faces cross each other
to permit the flanges of a railway vehicle to
pass from one track to another.
• A gap is provided from throw to the nose of
crossing
• Check rails assures the correct movement and
guides the wheels properly.
25. Crossing - Components
• 2 Rails – Point rail, Splice rail are joined
• These are machined to form a nose.
• The point rail has its fine end slightly cut off to form a
blunt nose, with a thickness of 6 mm (1/4").
• The toe of the blunt nose is called the actual nose of
crossing (ANC) and the theoretical point where gauge
faces from both sides intersect is called the
theoretical nose of crossing (TNC).
• The ‘V’ rail is planed to a depth of 6 mm (1/4") at the nose
and runs out in 89 mm to stop a wheel running in the
facing direction from hitting the nose.
26.
27. Crossings - Components
• Two wing rails consisting of a right-hand and a
left-hand wing rail that converge to form a
throat and diverge again on either side of the
nose.
• Wing rails are flared at the ends to facilitate
the entry and exit of the flanged wheel in the
gap.
• A pair of check rails are used to guide the
wheels
28. Crossing - Types
• Based on the angle of crossing
– Acute angle crossing: (or V crossing)
• 2 rail gauge faces cross at acute angle
– Obtuse angle or Diamond crossing
• 2 gauge faces meet at obtuse angle
– Square crossing
• Two tracks cross at right angles
29. Crossings - Types
• For manufacturing purposes
– Built up crossing:
• 2 wing rails, a V section consisting of point and splice
rails are assembled together by means of bolts and
distance blocks to form a crossing.
• Low cost
• Easy to place and repair.
• Bolts require frequent checking.
• If wear is more than 10mm renewal required.
30. Crossings - Types
– Cast steel crossing:
• One piece crossing with no bolts and require little
maintenance.
• More rigid as it is one single piece.
• High initial cost
• High maintenance cost
• Replaced by Cast Manganese Steel crossings these days
– Combined rail and cast crossing
• Combination of built up and cast steel crossing
• Consists of a cast steel nose finished to ordinary rail
faces
31. Crossing - Types
• CMS Crossings
– Due to heavy loads and traffic, normal manganese
rails are quickly wearing out
– CMS crossings possess high strength, high resistance
to wear, longer life.
– Avg life of CMS crossing is 4 times that of built up
crossing
– CMS crossings are free from bolts and other
components which normally get loose as a result of
traffic.
– High initial cost, but less maintenance
– Standardized in Indian Railways
32. Crossing- Types
• According to Diversion:
– In a spring crossing, one wing rail is movable and
is held against the V of the crossing with a strong
helical spring while the other wing rail is fixed.
35. Crossings:
Scissors Crossing(Double cross):
This type of crossing consists
4 pair of switch
6 Acute crossings
2 Obtuse crossings
check rails
And this type is use at goods yard.
According to Diversion
37. Crossings:
Diamond Crossing
When two tracks crosses each
other at less than 90 angle then
it forms diamond shape so it
is called Diamond Crossing
According to Diversion
