TE

6.  Combination of rails, fitted on sleepers and
resting on ballast and subgrade
 Rails are joined in a series using fish bolts
 Rails are connected to sleepers using fastenings
 Rails act as a girder and transfer wheel load to
sleepers
 Sleepers hold the rails in proper position and
transmit load from rails to ballast
 Ballast holds the sleepers and distribute load
over the formation

8.  Gauge should be correct and uniform
 Rails should in proper level
 Gradient must be uniform and as gentle as possible
 Track must be elastic in order to absorb shock and
vibrations
 Radii and SE must be properly designed
 Proper drainage must be provided
 Joints are to be properly designed
 All the materials using must have sufficient BC
 Adequate provision for easy renewals and
replacements
 Track should be strong, low IC and MC

9.  Defined as the clear distance between inner or
running faces of two track rails

10.  Cost of construction
 Cost of structures – bridges, tunnels, buildings…
 Cost of earthwork
 Land acquisition
 Rolling stock
 Volume and nature of traffic – volume & load
 Development of the areas – less populated
 Physical features of the country
 Speed of movement
 directly proportional to gauge
 Speed is function of dia. of wheel
 Wheel dia. Is 0.75 times that of gauge

11.  Delay, cost and hardship in transhipping passengers
and goods
 Difficulties in loading and unloading of goods
 Labour charges are saved
 Possibility of thefts, misplacement while changing
from one train to another train
 Large sheds to store goods are not req.
 Labour strikes don't affect service & operation
 Surplus wagons cannot be used effectively
 Duplication of resources like platforms,
arrangements, clocks etc. are saved
 No wastage of time during military operations
 Quite expensive to convert at later stage as rolling
stock, widening of bridges and tunnels are difficult

12.  Distance b/w inside edges of wheel flanges is
generally kept lesser than gauge of track
 Generally 1cm on either side
 Wheels are coned at a slope of 1 in 20

14.  To reduce wear and tear of wheel flanges and
rails due to rubbing action
 To provide possibility of lateral movement of
axle with its wheels
 To prevent wheels from slipping to some
extent

16.  To transmit the load from rolling stock to
sleepers
 To provide hard, smooth, uniform surface for
the wheels to roll
 To give minimum wear to rail material
 To bear the stresses due to vertical loads,
breaking forces and thermal stresses

17.  Very stiff i.e. bearing capacity must be high
 Proper composition of steel (Carbon content)
 Capable of withstanding lateral forces
 Tensile strength should not be less than
72kg/cm2
 Should withstand “falling weight test or tup
test” without fracture
 Distribution of material in head, web and foot of
the rail should be balanced
 Web of rails should be thicker
 Foot should be wider
 Wearing surface i.e head must be harder

18. 1) Double headed rails(D.H. Rails)
2) Bull headed rails(B.H. Rails)
3) Flat footed rails(F.F. Rails)

19. Looks like dumb bell
Idea is to use another
head when one head is
worn out during course
of time
But after usage, lower
head got dented(eroded)
Smooth running was
impossible
So introduced B.H rails

20. More metal is added at top
compared to lower head to
increase the stresses
More solid and smoother
track
Chairs and keys are req. so
sleepers have longer life
Hence costlier
But after usage, they found
that lateral stability is very
less
So introduced F.F rails

22. Foot is made thinner and wider
than head
Distributes the load to greater
number of sleepers
Results in greater stability
Fittings of rails to sleepers is
easier
No chairs and keys req.
Invented by CHARLES
VIGNOLES
Hence called as VIGNOSE rails
90% railway tracks in world
are made of these rails only

23.  Various types of rails are in use by Indian Railways
 Every bit of material in the section is to be utilized
 90R(44.61kg/m) --- 100kmph for 20 to 25 years
 50R, 60R and 75R are also in use
 To overcome inc. demand for heavier and faster
traffic:
 52MR(52kg/m) --- 130kmph for 20-25 years
 60MR(60kg/m) --- 160kmph for 20-25 years
 R- British rail as per Revised British Standards(RBS)
 MR – Metric rail as per IRS

24.  Rail is designated by its weight per unit length
 Various factors to be considered in deciding:
 Speed of the train
 Gauge of the track
 Axle load and nature of traffic
 Type of rails
 Spacing of sleepers
 Max. permissible wear on top of rails(5% of weight is
allowed)
 Wt. of rail/locomotive axle= 1/510

25.  Longer rail lengths are preferred to shorter one’s
 Stronger and economy
 Comfort to passengers increases
 Length of rails is governed by:
 Manufacturing cost is reasonable
 Transportation facilities
 Lifting, handling during loading & unloading
 Standard length of rails in India are:
 Length = 12.8m for B.G
 Length = 11.89m for M.G
 Proposed to inc. up-to 25m, USA & UK uses 30m
 Other alternative is to use welding as it eliminates
difficulty of transportation, lifting & handling

26. 1) Crushed heads:
2) Square or angular break:
3) Split heads:
4) Split web:
5) Horizontal fissures:
6) Transverse fissures:
7) Flowing metal in heads:
8) Horizontal cracks:

27.  Prominent defects of rails
 Heavy axle loads & speed trains have more impact
 Classification of wear
 On the basis of location
 On the basis of position of wear

28.  Wear is prominent on the following locations:
 On sharp curves
 On gradients
 On approaches to stations, brakes are frequently applied
 In tunnels
 Where sand is used at damp rails to produce more friction
but it gives more wear
 Gases emitting from engine being confined attack the metal
 In coastal area – action of sea breeze, corrosion of metal
takes place
 On weak foundations – uneven sinking of rails into
ground

29.  Following are the positions of wear on rails:
1) Wear on top or head of rail
2) Wear at the end of rails
3) Wear on the sides of the head
1) Wear on top of rails: occurs on straight and
curved tracks

30.  On Straight or tangent tracks:
 Due to flow of metal: elastic limits exceed and hence
plastic flow of metal takes place and burrs are formed
 Heavy axle loads and its recurring impacts
 Abrasion of rolling wheels
 Brake application @ skidding
 Use of sand
 Corrosion of rails
 Weak track – loose packing of ballast & fittings to
sleepers
 On curves
 Slipping or skidding of wheels
 Effect of centrifugal force i.e inner & outer wheels
pressure

31.  Wheel jumps over the gap giving blow to the
end of rail
 End of rail get battered
 Due to
 Loose fish plates and fish bolts
 Heavy loads and large joint openings
 Difference in rail levels at joints
 Poor maintenance of track

32.  Prominent at curves
 Most destructive
 Inner rails have more thrust
 Slipping and skidding of wheels at curves

33.  Rail joints are the weakest part in the railway track
 It is the joint made between two rails
 gap of 1.5 to 3mm for expansion
 Strength of rail joint is 50% of strength of rail
 Generally we use 2 fish plates and 4 fish bolts

34. Ideal joint provides same strength & stiffness as a normal rail
 2 rails should be in line – vertically and horizontally
 Should permit expansion and contraction of rails
during temperature changes
 Cheap and economical
 Require less maintenance
 Should be easily disconnect able without disturbing
whole track
 Rail ends shouldn’t get battered(worn out)
 Less wear and tear especially when fittings become
loose

35.  Supported rail joint: when
rail ends rest on a single
sleeper called as
“joint sleeper”
 Suspended Rail Joint:
“Shoulder sleepers”
Generally used for timber
And steel sleepers

36.  Bridge joint: same as suspended joint but we use a
extra plate called as “bridge plate”
 Base joint: similar to bridge joint
 Inner fish plates are of bar type
 Outer fish plates are of angular type
 plate is further extended to both bridge plate and sleeper
 Welded rail joints: Best rail joint
 Compromise Joint: when 2 different rail sections
are to be joined

37.  Insulated joint: to stop
flow of current beyond
track circuit part
 Square joints: joint of one rail is directly
opposite to other rail track
 Staggered or Broken joints: joints of one rail
track are not directly opposite to joints of other
rail track. Generally @ curves

38.  To increase length of rail by joining 2 or more
rails
 It reduces no. of joints
 Req. less no. of fish plates
 Economy and strength
 Repair of worn out or damaged rails

39.  It is a perfect joint and inc. life of rail
 Reduction in maintenance cost by 20 to 40%
 Reduces the creep
 Expansion effect due to temperature will
decrease
 Riding quality is increased
 Wear of the rail decreases
 Initial cost of the track also decreases

40.  Short welded rails(SWR): rails of 3, 5 or 10 are
welded
 Standard Indian railways prescribes 3 rails
 Long welded rails(LWR): min. length of 300m
and max. of 1000m
 Continuous welded rails(CWR): longer than
1000m.
 Sometimes they are in b/w 2 stations

41. 1) Electric arc welding
2) Oxy- acetylene welding
3) Flash butt welding
4) Chemical or thermit welding

42.  Metal arc welding
 Current is passed through rails and a thin rod
known as electrode at same time
 Due to heat, electrode gets melted and deposits
on rail, forming a firm bond
 Used for building up worn out rails

43.  Gas pressure welding
 Heat is produced by combining oxygen &
acetylene gas
 Due to heat, electrode gets melted and deposits
on rail, forming a firm bond
 Used for building up worn out rails
 Best form mobility
point of view

44.  Powerful current is passed through rails
 Rail ends get heated up resulting in a flash
 Current is stopped and both the rails are
pressed together under a pressure of 20 tonnes
 Heavy machinery req.
 So not economical for small works

45.  Use of chemicals like aluminium & iron oxide
 Both the chemicals are mixed in powder form
and ignited
 Exothermic reaction takes place and iron gets
separated & deposits in rail gap
 Rail ends are also to be heated
 economical

46. Functions of Sleepers:
 To transfer the load from rails to ballast
 Acts as elastic medium & absorbs blows and vibrations
 Hold rails in correct gauge and alignment
 Firm and even support to rails
Requirement of Good Sleeper
 Strong enough to take load
 Weight must be lesser
 Bearing area must not be crushed
 Initial and maintenance cost must be less
 Should resist vibrations and shocks
 Fastenings must be min.
 Should permit track circuiting
 Should not be damaged by insects easily

47.  Wooden Sleepers
 Metal Sleepers
 Steel
 Cast Iron
 Concrete Sleepers
 R.C.C
 Pre-stressed

48.  Also called as timber sleepers and its life depends on
the quality of timber used
 Hard wood(sal & teak) and soft wood(chir & deodar)
 Advantages:
 Good for track circuiting
 Laying, packing and lifting is easy
 req. less fastenings
 Good absorber of shocks and vibrations & give less noisy track
 Easily available
 No corrosion
 Disadvantages:
 Scrap value is less
 Subjected to wear, decay, attack by White ants
 Less life i.e. 12-15 years
 High maintenance cost
 Track is easily disturbed

49.  Made of 6mm thick steel sheets with both ends bent
 Advantages:
 More strength and durability
 More life (25-30years)
 Performance of fittings is better, hence less creep occurs
 Economical
 No effect of termites
 Have good scrap value
 Disadvantages:
 Fittings are greater in number, hence difficult to maintain
 Corrosion
 More cost compared to wooden
 Not suitable for track circuiting

50.  Advantages:
 Maintenance cost is less
 Free from natural decay
 Suitable for track circuiting
 More life- 40 to 60 years
 No corrosion
 Can take heavier loads, so fast moving trains
 Disadvantages:
 Scrap value is nil
 Heavy weight, 2.5 to 3 times heavier
 Handling is difficult
 Fittings req are more

51.  No. of sleepers used per rail length
 Indicated with M+x or N+x
 Varies from (M+4) to (M+7)
 Depends on speed of train, size of rail, type of
joint, strength of sleepers and axle loading

52.  Material placed and packed below and around
sleepers to distribute the load from sleepers to
formation and drainage giving stability to track
 Functions of Ballast:
 Transfer the load
 Holds the sleepers in position and provides Hard
bed for sleepers to rest on
 Elasticity to track and thereby improving riding
comfort
 Prevent growth of vegetation
 Good drainage

53.  Hard without getting crushed
 Should not make the track dusty or muddy
 Durable towards abrasion and weathering action
 No chemical affect on rails and sleepers
 Good drainage of water
 Cheap and economical
 Near by locality
 Angular or rough surface
 Non porous and non absorbent
 Easily packed in position

54.  Size of ballast varies from 1.9 cm to 5.1cm
 Size of stone ballast should be 5 cm for wooden
sleepers, 4cm for metal & concrete sleepers, 2.5cms
at crossings
 Section of ballast – Depth and width
 Depth inc. load bearing capacity and width
implies lateral stability to track
 Width will be around 38 -43cms
 America- depth equal to sleeper spacing
 India – not this recommendation
 Quantity of ballast req. Per m length is 1.036m3

55.  Sleeper spacing = width of sleeper + 2 * Depth
 Sleeper dimensions = 275 * 25*12.5

56.  Broken stone
 Gravel or river pebbels
 Sand
 Ashes
 Moorum
 Kankar
 Brick ballast
 Blast furnace slag
 Selected earth

57.  Quantity of ballast is reduced due to:
 Blowing away of ballast by movement of trains
 Penetration of ballast in the formation
 Lost due to rain water and wind