The document discusses various aspects of railways including history, components of a permanent way, track structure standards, types of rails used, design of rails, and functions of sleepers. It provides details on the first Indian railway line opened in 1853 between Bombay and Thane. It also compares road and rail transport and covers feasibility studies for railway projects. The permanent way components discussed are subgrade, ballast, sleepers, rails, and fixtures/fastenings. Track structure standards are categorized into groups based on sanctioned speed. Types of rails described are double headed, bull headed, and flat footed rails.

1. UNIT II

2. Railway
 A permanent way.
 Transport Passengers and Goods.

3. Railway Engineering
 Design, Construction & Maintenance of Railway
Tracks
 Safe & Efficient movement of Trains.
 Railway and Roads – Ground Transportation.

4. History of Indian Railway
 First Indian Railway was opened on 16th April 1853.
 One Steam Engine
 Four Coaches
 Bombay to Thane (34 km)
 Owner- Military Engineers of the East India Company,
later - British Indian Army
 Indian Railway- Indian State Owned Enterprise owned
and operated by Govt. of India through Ministry of
Railway.

5. Roadways V/S Railways
1. Suitable for only from
one station to another
station.
2. Load carrying capacity
is more than roadways.
3. Suitable for long
distance
4. Maintenance cost is
more.
5. Limitation on the
steeper gradient
1. Suitable for all
types of traffic.
2. Load carrying
capacity is less.
3. Suitable for any
distance.
4. Maintenance cost
is less.
5. Suitable for
steeper gradients.

6. Feasibility Studies
 An assessment of the practicality of a proposed plan or
method.
 Preliminary Study

7.  Large or complex project / doubt or controversy
regarding proposed development
 To determine if the construction is feasible
 To establish the technical and financial basis for the
rest of the design and executing process of the works.
 In the Past feasibility studies for Railway projects have
been developed on ad hoc basis – no standardize
approach.
 It results in High Risk Failure, Project runs very late,
widely over budget.

8. Feasibility
Studies
Economic
Feasibility
Population & its
Distribution
Agricultural and
industrial
development, per
capita income
Financial
Feasibility
Living standards of
the society. sources
of income
Revenue from
taxation on railway
transport
Social Feasibility
Acceptance of
change in the
society
Land Acquisition
Social issue, Value
for the land
Traffic Survey
Accurate
determination of
potential traffic
along various
traffic routes
Distribution,
density,
affordability of
population

9. Permanent Way
 Combination of rails, fitted on sleepers and resting on
ballast and sub-grade is called the railway track or
permanent way.

10. Component parts of a
permanent way
 Subgrade
 Ballast
 Sleepers
 Rails
 Fixture and Fastening

11. Component parts of a permanent
way

13. Component parts of a permanent
way
 In a permanent way, rails are joined either by welding
or by using fish plates and are fixed with sleepers by
using different types of fastenings.
 Sleepers are properly placed and packed with ballast.
Ballast is placed on the prepared subgrade called
formation.

14. Requirements of an ideal permanent
way
 (i) The gauge of the track should be uniform and
correct.
 (ii) Both the rails should be at the same level in a
straight track.
 (iii) On curves proper superelevation should be
provided to the outer rail.
 (iv) The permanent way should be properly designed
so that the load of the train is uniformly distributed
over the two rails.

15. Requirements of an ideal
permanent way
 (v) The track should have enough lateral strength so
that it can maintain its stability even with variation in
temperature and other factors.
 (vi) The radii and super elevation, provided on curves,
should be properly designed.
 (vii) The track must have certain amount of elasticity
to absorb the shocks and vibrations of running trains.

16. Requirements of an ideal
permanent way
 (viii) All joints, points and crossings should be properly
designed.
 (ix) Drainage system of permanent way should be perfect
so that the stability of the track is not affected by water
logging.
 (x) All the components of permanent way should satisfy
the design requirements.
 (xi) It should have adequate provision for easy renewals
and repairs.

17. Track Structure
 The maximum distance between the running faces of
the two rails of a permanent way is called GAUGE.
 The track standards had been laid down in 1973 after
review by a committee of Directors, Chief Engineers.
 These track standards were reviewed based on railway
reforms committee recommendations and on the
recommendations of 60 th track standard
committee

18. Track Structure
 The railway board accordingly laid down in 1985 the
track standards for various routes which were made
applicable for new works included in 1986-87 Budget.
 These triple gauges exhibit the hierarchical
importance of the rail routes.

19. Hierarchy
 The double track broad gauge today linking the
metropolitan cities and major ports comes on the top of
the list
 Followed by single track broad gauge branch line on
peripheral trunk routes,
 Meter gauge double track lines,
 Meter gauge single track routes and
 Narrow gauge rail lines.

20. Gauge width
 Broad gauge is 1.44 meters in width.
 Meter gauge is 1 meter which, the name itself
denotes.
 Narrow gauge is used in mountain or hill trains which
is less than a meter and it's width is 0.79 meters.

21. Group `A'-For a sanctioned speed of
160 km. per hour
 The minimum rail section to be adopted will be 60 Kg.
in section having traffic density of over 20 GMT and 52
Kgs in other sections.
 The minimum sleeper density shall be 1,660 numbers
per Km.
 The ballast cushion shall be 30 cm.

22. Group `B'-For a sanctioned speed of
130 km. per hour
 The minimum rail section to be adopted will be 60 Kg.
in sections having traffic density of over 20 GMT and
52 Kg. in other sections.
 The minimum sleeper density shall be M+7.
 The ballast cushion shall be 25 cm.

23. Group `C'-Suburban Sections
 The minimum rail section to be adopted will be 60 Kg.
in sections having traffic density of over 20 GMT and
52 Kg. in other sections.
 The minimum sleeper density shall be M + 7.
 The ballast cushion shall be 25 cm.

24. Group `D'-Where the maximum
sanctioned speed is 100 Kms/hour, as
at present
 The minimum rail section to be adopted will be
 60 Kg in sections having traffic density of over 20 GMT,
 52 Kg. in sections having traffic density from 10 to 20
GMT and
 44.5 Kg in sections having traffic density of less than 10
GMT.
 The minimum sleeper density shall be
 M + 7 in sections having traffic density above 10 GMT
and
 M + 4 in sections having traffic density below 10 GMT.
 The ballast cushion shall be 20 cm.

25. Double headed rails(D.H. Rails)
 The rails having their head and foot of same
dimensions are known as double headed rail (D.H.)
 The idea behind using these rails was that when the
head had worn out due to rubbing action of wheels,
the rails could be inverted and reused.
 But by experience it was found that their foot could
not be used as running surface because it also got
corrugated under the impact of wheel loads.

26. Double headed rails(D.H. Rails)

27. Bull headed rails(B.H.Rails)
 The rail section whose head dimensions are more than
that of their foot are called bull headed rails.
 In this type of rail the head is made little thicker and
stronger than the lower part by adding more metal to
it.
 These rails also require chairs for holding them in
position.
 Bull headed rails are especially used for making points
and crossings.

28. Bull headed rails(B.H.Rails)

29. Flat Footed Rails
 The rail sections having their foot rolled to flat are called
flat footed.
 It was initially thought that the flat footed rails could be
fixed directly to wooden sleepers and would eliminate
chairs and keys required for the B.H. rails.
 But later on, it was observed that heavy train loads caused
the foot of the rail to sink into the sleepers and making the
spikes loose.
 To remove this defect, steel bearing plates were used in
between flat footed rails and the wooden sleeper. These
rails are most commonly used in India.

30. Flat Footed Rails

31. DESIGN OF RAIL
 The rail is designated by its weight per unit length. In
metric units it is in kg per meter. A 52 kg/m rail
denotes that it has a weight of 52 kg per meter.
 The weight of a rail and its section is decided after
considerations such as the following:
 (a) Heaviest axle load
 (b) Maximum permissible speed
 (c) Depth of ballast cushion
 (d) Type and spacing of sleepers
 (e) Other miscellaneous factors

32. DESIGN OF RAIL
 The standard rail sections in use on Indian Railways are 60 kg,
52 kg, 90 R, 75 R, 60 R and 50 R. The two heavier rail sections,
60 kg and 52 kg, were recently introduced and are designated in
metric units.
 Other rails are designed as per the revised British Standard
specifications and are designated in FPS units though their
dimensions and weight are now in metric units. In the
nomenclature 90 R, 75 R, etc., R stands for revised British
specifications.
 The brand marks on the rails are to be rolled in letters at least 20
mm in size and 1.5 mm in height at intervals of 1.5 to 3.0 m.

33. DESIGN OF RAIL
 Every rail rolled has a brand on its web, which is repeated
at intervals. As per IRS–T–12–88, the brand marks are as
follows:
IRS-52 kg – 710 – TISCO – II 1991 ® OB.
 The definitions for the various abbreviations are as follows:
 (a) IRS-52-kg: Number of IRS rail section, i.e., 52 kg
 (b) 710: Grade of rail section, i.e., 710 or 880
 (c) TISCO: Manufacturer’s name, e.g., Tata Iron and Steel Co.
 (d) II 1991: Month and year of manufacture (February 1991)
 (e) ®: An arrow showing the direction of the top .
 (f) OB: Process of steel making, e.g., open hearth basic (OB)

34. SLEEPERS
 Sleepers are transverse members of the track placed
below the rails to support and fix them in position.
 They transmit wheel load from the rails to the ballast.

35. FUNCTIONS OF SLEEPERS
(i) To hold the rails to proper gauge.
(ii) To transfer the loads from rails to the ballast.
(iii) To support and fix the rails in proper position.
(iv) To keep the rails at a proper level in straight tracks and at
proper super elevation on curves.
(v) To provide elastic medium between the rails and the
ballast.
(vi) To provide stability to the permanent way on the whole.

36. REQUIREMENTS OF GOOD
SLEEPERS
 (i) The sleepers should be sufficiently strong to act as a
beam under loads.
 (ii) The sleepers should be economical.
 (iii) They should maintain correct gauge.
 (iv) They should provide sufficient bearing area for the
rail.

37. REQUIREMENTS OF GOOD
SLEEPERS
 (v) The sleepers should have sufficient weight for stability.
 (vi) Sleepers should facilitate easy fixing and taking out of
rails without disturbing them.
 (vii) They should facilitate easy removal and replacement
of ballast.
 (viii) They should not be pushed out easily of their position
in any direction under maximum forces of the moving
trains.

38. REQUIREMENTS OF GOOD
SLEEPERS
 ix) They should be able to resist impact and vibrations
of moving trains.
 (x) They should be suitable to each type of ballast.

39. TYPES OF SLEEPERS

40. RCC

41. CAST IRON SLEEPERS

42. FASTENINGS
 Fixtures and fastenings are fittings required for joining
of rails end to end and also for fixing the rails to
sleepers in a track.

43. FUNCTIONS OF FIXTURES AND
FASTENINGS
 (i) To join the rails end to end to form full length of track.
 (ii) To fix the rails to sleepers.
 (iii) To maintain the correct alignment of the track.
 (iv) To provide proper expansion gap between rails.
 (v) To maintain the required tilt of rails.
 (vi) To set the points and crossings in proper position.

44. TYPES OF FIXTURES AND
FASTENING
 1. Fish plates
 2. Bearing plates
 3. Spikes
 4. Chairs
 5. Bolts
 6. Keys
 7. Anticreepers

45. Fish plates
 A fish plate is a metal or wooden plate that is bolted to
the sides at the ends of two rails or beams, to join
them.

46. Spikes
 A rail spike (also known as a cut spike or crampon) is a
large nail with an offset head that is used to secure
rails and base plates to railroad ties in the track.

47. Bearing plate
 These are the plates which are provided in between the
flat footed rails and wooden sleepers.

48. Bolts
 Bolts are used for connecting fish plates to the rails at
rail joint, bearing plates and chairs to wooden sleepers
etc.

49. Chairs
 Cast iron chair (C.I chairs).
 Slide chairs

50. Keys
 These are small tapered pieces of timber or steel used
to fix rails to chairs on metal sleepers.
 Keys are of two types :
 (i) wooden keys: Wooden keys are small straight or
tapered pieces of timber. These are cheap and Easily
prepared. These are not strong and become loose under
vibrations. These require frequent maintenance.
Wooden keys are not used now-a days in Indian
Railways.

51. Keys
 ii) Metal keys : Metal keys are small tapered or spring
like pieces of steel. These keys are much more durable
than wooden keys.
 Metal keys are of two types:
 (i) Stuart`s key and
 (ii) Morgan key

52. Coning of wheels
 "Coning of wheels" is what allows a train to take a turn
without slipping off its tracks.
 The thread of the wheels of a railway vehicle are not
flat but sloped like a cone.
 The wheels generally, remain central on a straight and
level surface and the circumference of the threads of
both the vehicle are equal.

53. Coning of wheels
 However on a curve , the outer wheel has to negotiate
more distance as compared to the inner wheel.
 Due to centrifugal force on a curve, the circumference
of the thread of the outer wheel thus becomes greater
than that of the inner wheel.
 This helps the outer wheel to travel longer distance
than the inner wheel.

54. Coning of wheels
 Disadvantages
 i) The outer rail will have more pressure while the
inner rail will have lesser pressure.
 (ii) Owing to the centrifugal strength, the parallel
components incline to turn the rail out and gauge has
broadening tendency.
 (iii) Due to this condition if the voids sleepers have no
base plate beneath the edge of the rail they will be
damaged.

55. Coning of wheels

56. Tilting of Rails
 If the rails are laid flat, coning of the wheels will
subject the rails to eccentric loading .
 Tilting is achieved by using inclined base plates.
 The slope of the base plate is 1 in 20 which is the slope
of the coned surface of the wheel.

57. Tilting of Rails
 Advantages of Tilting of Rails:
 The tilting of rails increases the life of sleepers and
rails.
 It maintains the gauge properly.
 The wear of the head of the rail is uniform due to
tilting of rails.

58. Tilting of Rails

59. Tilting of Rails

60. BALLAST
 Ballast is the granular material usually broken stone or
any other suitable material which is spread on the top
of railway formation and around the sleepers.

61. FUNCTIONS OF BALLAST
 (i) To hold the sleepers in position and preventing the
lateral and longitudinal movement.
 (ii) To distribute the axle load uniform from sleepers to
a large area of formation.
 (iii) To provide elasticity to the track. It acts as an
elastic mat between subgrade and sleepers.

62. FUNCTIONS OF BALLAST
 (iv) To provide easy means of maintaining the correct
levels of the two rails in a track.
 (v) To drain rain water from the track.
 (vi) To prevent the growth of weeds inside the track..

63. REQUIREMENT GOOD BALLAST
 i) It should have sufficient strength to resist crushing under
heavy loads of moving trains.
 (ii) It should be durable enough to resist abrasion and
weathering action.
 (iii) It should have rough and angular surface so as to
provide good lateral and longitudinal stability to the
sleepers.
 (iv) It should have good workability so that it can be easily
spread of formation.

64. REQUIREMENT GOOD BALLAST
 (v) It should be cheaply available in sufficient quantity
near and along the track.
 (vi) It should not make the track dusty or muddy due
to its crushing to powder under wheel loads.
 (vii) It should allow for easy and quick drainage of the
track.
 (viii) It should not have any chemical action on metal
sleepers and rails.

65. TYPES OF BALLAST
 Broken stone.
 Gravel
 Sand
 Ashes or cinders
 Kankar
 Murum
 Blast furnace slag
 Brick ballast
 Selected earth

66. BROKEN STONE
 This is the best type of ballast as it possesses all the
characteristics of a good ballast.
 It holds the track to correct alignment and gradient
due to its high interlocking action.
 The stones which are non porous, hard and do not
flake on breaking should be used.
 Igneous rocks such as granite, quartzite and trap make
excellent ballast.
 This type of ballast is used for high speed tracks.

67. BROKEN STONE
 ADVANTAGES
 a. It is hard and resist crushing under heavy loads.
 b. It has angular and rough surface and hence gives
more stability to the sleepers.
 c. Its drainage property is excellent.
 DISADVANTAGES
 (a) It is expensive.
 (b) It is not so easily available

68. GRAVEL
 Gravel is the second best material for ballast.
 This is obtained either from river beds or from gravel pits
and has smooth rounded fragments.
 Gravel obtained from pits usually contains earth which
should be removed by washing.
 Gravel obtained from river beds is screened and required
size gravel is used.
 Larger size gravels are broken into required size.
 Round edges gravels are broken to increase their
interlocking action.

69. GRAVEL
 ADVANTAGES
 (a) Gravel is cheaper than stone ballast.
 (b) The drainage property of gravel excellent.
 (c) It holds the track to correct alignment and gradient.
 (d) It is easy to use gravel ballast than stone ballast at
certain places where formation is unstable.
 DISADVANTAGES
 (a) It requires screening before use due to large variation in
size.
 (b) Gravel obtained from pits requires washing.
 (c) Due to round faces the packing under sleepers is loose.
 (d) Gravel easily roll down due to vibrations.

70. Pre-stressed concrete sleepers
 Pre-stressed concrete sleepers are now-a-days
extensively used in Indian Railways.
 These sleepers have high initial cost but are very cheap
in long run due to their long life.
 In these sleepers, high tension steel wires are used.
 These wires are stretched by hydraulic jack to give
necessary tension in the wires.
 The concrete is then put under a very high initial
compression.
 These sleepers are heavily damaged in case of
derailment or accidents of trains.

71. Welding of Rail Joint
 The purpose of welding is to join rail ends together by
the application of heat and thus eliminate the
disadvantages of fish plate rail joints.
 There are four welding methods used on railways.
 (a) Gas pressure welding
 (b) Electric arc or metal arc welding
 (c) Flash butt welding
 (d) Thermal welding

72. PURPOSE
 To increase length of rail by joining two or more rails.
 To repair the worn out or damaged rails and thus
increase their life.
 To build up worn out points and rails on the sharp
curves.
 To build up the burnt portion of rail head caused due
to slippage of wheels over the rail or other defects or
spots in rail steel.

73. ADVANTAGES
 (1)It satisfies the conditions of a perfect joint and
hence increases the life of the rail and reduces the
maintenance cost by @ 20 to 40%.
 (2) It reduces the creep as the length of rail increases.
 (3) Expansion effect due to temperature is also
reduced which also reduces the creep.

74. ADVANTAGES
 (6) Increase the life of rails due to decrease wear.
 (7) Facilitates track circuiting on electrified tracks.
 (9) Welded rails on curves is under investigation,
Maximum curve radius may be welded depending
upon resistance a lateral displacement of track.
 (10) Long rail lengths dampen the intensity of high
frequency vibrations due to moving length.

75. Electric Arc welding
 In this method current is passed through rail as well as
through electrode. As electrode approaches the rail an
electric arc is formed and with the heat electrode gets
melted and the molten metal deposits on the rail,
providing a firm bond.
 Easy to handle
 This consists of an engine, generator and some
accessories.

76. Electric Arc welding
 Used for building up worn out points and crossing
damaged rails and other small welding operations.

77. Oxy-acetylene welding
 Intense heat is produced by combining the oxygen and
acetylene gas which melts electrode and deposits the
molten metal on rails.
 This plant consists of two cylinders, best in mobility
point of view.
 Used for repairing worn out or damaged part of points
and crossing.
 This is specially useful for cutting of steel.

78. Flash welding
 Powerful current is passed through two rails, here ends
of which are to be joined together.
 Heating upto required temperature they are brought
in contact resulting in flash then current is stopped
and rails are pressed together under a pressure of 20T
 Most satisfactory.
 This method of welding involves heavy welding plant
and that too immobile and hence uneconomical for
small jobs at site.

79. Chemical or Termite Welding
 This involves the use of chemical, aluminum and iron
oxide.
 Aluminum and iron oxide is mixed in a powder form
and ignited. On ignition the chemical reaction takes
place produces intense heat because this reaction is
exothermic in nature.
 After reaction the Fe gets separated and is deposited in
the gap of rail ends which are preheated.

80. Chemical or Termite Welding
 Actually these two ends with the chemical mixture in
between the gap are entrapped in mould to prevent
the flow of mixture a shown in fig.

81. Short Welded Rails (SWR)
 Technical advantage that a welded track possess over
the fish plated track necessitated the development of
welded joints of rail. This first stage of development in
this direction is short welded rails (S. W. R.).
 A short welded rails is a welded rail which contracts
and expands throughout its entire length due to
temperature variations.

82. Long Welded Rails (LWR)
 Long welded rails is a welded rails of which the central
part does not undergo any longitudinal movement due
to temperature variations.
 The concept behind development of long welded rails
is the locking up of stresses which resists longitudinal
movement of rail.

83. Continuously Welded Rails (CWR)
 On Indian Railways the length of long welded rails has
been limited to one km only because of panels upto
this length are considered convenient for the purpose
of laying distressing and from maintenance point of
view.
 The welded panels longer than one km that have been
tried by Indian railways and are called as Continuously
Welded Rails.

84. Points crossings and turnouts
 Points and crossings are provided to help for
transferring railway vehicles from one track to another.
 The tracks may be parallel to, diverging from, or
converging with each other.
 These are necessary because the wheels of railway
vehicles require special arrangement in order to
navigate their way on the rails.

85. Points crossings and turnouts
 The points or switches aid in diverting the vehicles and
the crossings provide gaps in the rails so as to help the
flanged wheels to roll over them.
 Furnace is used at the bottom of rails for eating the
ends, After the mixture is solidifies the mould is
removed and surface girding is done.
 Used in renewal of rails. This plant is mobile in nature
and can be used site for welding of rails

86. Switches / Points
 A set of points or switches consists of the following main
constituents
 (a) A pair of stock rails, AB and CD, made of medium-
manganese steel.
 (b) A pair of tongue rails, PQ and RS, also known as switch
rails, made of medium-manganese steel.
 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.

87. Switches / Points
 (c) A pair of heel blocks which hold the heel of the tongue
rails at the standard clearance or distance from the stock
rails.
 (d) A number of slide chairs to support the tongue rail and
enable its movement towards or away from the stock rail.
 (e) 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.
 (f) A gauge tie plate to fix gauges and ensure correct gauge
at the points.

88. Switches / Points

89. Crossing
 A crossing or frog is a device introduced at the point where
two gauge faces cross each other to permit the railway
vehicle to pass from one track to another.
 Component Parts of a Crossing
 (i) A vee piece
 (ii) A point rail
 (iii) A splice rail
 (iv) Two check rails
 (v) Two wing rails
 (vi) Heel blocks at throat, nose and heel of crossing
 (vii) Chairs at crossing, at toe and at heel.

90.  Two rails, the point rail and splice rail, which are machined
to form a nose.
 The point rail ends at the nose, whereas the splice rail joins
it a little behind the nose.
 Theoretically, the points rail should end in a point and be
made as thin as possible, but such a knife edge of the point
rail would break off under the movement of traffic.
 The point rail, therefore, has its fine end slightly cut off to
form a blunt nose, with a thickness of 6 mm (1/4").

91.  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.

93. REQUIREMENTS OF IDEAL
CROSSING
 (i) Crossing assembly should be rigid enough to
withstand severe vibrations.
 (ii) Wing rails and nose of crossing should be able to
resist heavy wear due to movement of wheels, hence
should be manufactured of special steel (alloy steel).
 (iii) The nose of crossing should have adequate
thickness to take all stresses acting on the crossing.

94. TYPES OF CROSSINGS
 Crossings can be classified as follows:
 1. On the basis of shape of crossing
 (a) Square crossing
 (b) Acute angle or V-crossing or Frog
 (c) Obtuse angle or Diamond crossing
 2. On the basis of assembly of crossing
 (a) Ramped crossing
 (b) Spring or movable crossing.

95. Square Crossing
 Square crossing is formed when two straight tracks of
same or different gauge, cross each other at right
angles.
 This type of crossing should be avoided on main lines
because of heavy wear of rails.

97. Acute Angle Crossing
 Acute angle crossing is formed when left hand rail of
one track crosses right hand rail of another track at an
acute angle or vice versa.
 This type of crossing consists of a pair of wing rails, a
pair of check rails, a point rail and a splice rail.
 This crossing is widely used.

99. Obtuse Angle Crossing
 Obtuse angle crossing is formed when left hand rail of
one track crosses right hand rail of another track at an
obtuse angle or vice versa.
 This type of crossing consists mainly of two acute
angle and two obtuse angle angle crossings.
 This is also called Diamond crossing.

101. TURNOUT
 Turnout is an arrangement of points and crossings
with lead rails by which trains may be diverted from
one track to another moving in the facing direction.
 A turnout is left handed or right handed as the train
taking the turnout in the facing direction is diverted ti
the left or right of the main line.

102. Component parts of a Turnout
 Following are the component parts of a turnout
 (i) A pair of tongue rails
 (ii) A pair of stock rails
 (iii) Two check rails
 (iv) Four lead rails
 (v) A vee crossing

103.  (vi) Slide chairs
 (vii) Stretcher bar
 (viii) A pair of heel blocks
 (ix) Switch tie plate or gauge tie chair
 (x) Parts for operating points – Rods, cranks, levers etc.
 (xi) Locking system which includes locking box, lock bar,
plunger bar etc.
 (i) A Pair of Tongue Rails: The tongue rails along the stock
rails in a turnout form a pair of points or switches. The
tongue rails facilitate the diversion of a train from the main
track to a branch track.

104.  ii) A Pair of Stock Rails: They are the main rails to which
the tongue rails fit closely. The stock rails help in smooth
working of tongue rails.
 (iii) Two Check Rails: Check rails are provided adjacent to
the lead rails, one in main track and another in branch
track. These rails check the tendency of wheels to climb
over the crossing.
 (iv) Four Lead Rails: Outer straight lead rail, outer curve
lead rail, inner straight lead rail and inner curve lead rail
are the four lead rails provided in a turnout. The function
of these rails is to lead the track from heel of switches to
the toe of crossing.

105.  (v) A Vee Crossing: a Vee crossing is formed by two
wing rails, a point rail and a splice rail. It provides gaps
between the rails so that wheel flanges pass through
them without any obstruction.
 (vi) Slide Chairs: Slide chairs are provided to support
the tongue rail throughout their length and to allow
lateral movement for changing of points.