Point and crossing of railway

Points and Crossings
By:- Ramprasad Kumawat
(M.Tech)
DEPARTMENT OF
CIVIL ENGINEERING

Outline
• Point and crossing
• Turnout
• Types
– Left hand
– Right Hand
• Components
• Points and Switches
• Crossings

Points and Crossings
• Point and crossing are provided to transfer
train from one track to another.
• Point (Switch) :-The device that is use to
divert the wheels.
• Crossing:- Gaps in the rail that enables the
actual diversion

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.

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.

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

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

Types of Turnouts
• Depending on direction of movement of trains
from main tracks
– Right hand turnout
– Left hand turnout

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

Component Parts of a Turnout
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

• 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.

• 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.
• Heel Block :- These blocks are inserted
between the heel of the tongue rail and stock
rail. These are made of C.I. and are used to
provide a clear gap for the wheel flange.

• 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

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.

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.

Types of Switches
•There are Two types of switches:
– 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

• 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.

– 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.

• 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.

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.

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.

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

Crossing - Types
• Based on the angle of crossing :-
– Actual angle crossing: (or V crossing)
• 2 rail gauge faces cross at acute angle
– Obtuse angle crossing
• 2 gauge faces meet at obtuse angle
– Square crossing or Right angle crossing
• Two tracks cross at right angles

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.

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

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

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.

According to Diversion
Crossover Crossing:-
Function of this crossing is to connect
two parallel or diverging tracks.

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.

Diamond Crossing
When two tracks crosses each other at
less than 90 angle then it forms diamond shape
so it is called Diamond Crossing .

Gathering Lines:
When there is more than two track divert
from one line then it is called Gathering lines.

THANKS .
Email id :-
ramkumawat001@gmail.com

Point and crossing of railway

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