Transportation engineering , field of civil engineering
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Sep 18, 2024
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About This Presentation
Transportation engineering is a critical branch of civil engineering that focuses on the design, construction, and maintenance of transportation systems. These systems include roads, bridges, railways, airports, and other infrastructure that facilitate the movement of people and goods. As urbanizati...
Slide Content
1 1
Transportation Engineering - II
Lecture 1: Introduction
Transportation Engineering - II
Lecture 1: Introduction
Transportation Engineering
“The application of technological and scientific principles to the
planning, functional design, operation, and management of facilities for
any mode of transportation in order to provide for the safe, rapid,
comfortable, convenient, economical and environmentally compatible
movement of people and goods.”
2
“The application of technological and scientific principles to the
planning, functional design, operation, and management of facilities for
any mode of transportation in order to provide for the safe, rapid,
comfortable, convenient, economical and environmentally compatible
movement of people and goods.”
2
Rail Engineering
3
3
CODE: CE 354
Text Books:
1.Satish Chandra and M. Agrawal, Railway Engineering, Second Edition, Oxford
University Press, 2013.
2.Rangwala, S.C., Railway Engineering, Charotar Publishing House, Anand, India,
2008.
3.S.C.Saxena and S.Arora, Railway Engineering, Dhanpat Rai Publications (P) Ltd.
4
Text Books:
1.Satish Chandra and M. Agrawal, Railway Engineering, Second Edition, Oxford
University Press, 2013.
2.Rangwala, S.C., Railway Engineering, Charotar Publishing House, Anand, India,
2008.
3.S.C.Saxena and S.Arora, Railway Engineering, Dhanpat Rai Publications (P) Ltd.
4
Comparison of Railway and Highway
Feature Rail Transport Road Transport
Tractive Resistance
Right of way
Right of entry
Suitability to transportation
and goods
Gradient
Curves
Suitability of Hilly Regions
5
Feature Rail Transport Road Transport
Tractive Resistance
Right of way
Right of entry
Suitability to transportation
and goods
Gradient
Curves
Suitability of Hilly Regions
5
Comparison of Railway and Highway
Feature Rail Transport Road Transport
Tractive Resistance About 1/5 to 1/6 lower than highways 5 to 6 times higher than that of
wheels on rails
Right of way Width of right of way is lesser Require greater width for right of
way
Right of entry Right of entry is not free to all vehicles. free and flexible
Suitability to transportation
and goods
For long distances For shorter distances
Gradient Flatter or gentle (not more than 1 in
100)
Steeper gradients up to 1 in 30
Curves Limited up to only 10º Relatively much sharper curves
Suitability of Hilly Regions Not suitable More Suitable
6
Feature Rail Transport Road Transport
Tractive Resistance About 1/5 to 1/6 lower than highways 5 to 6 times higher than that of
wheels on rails
Right of way Width of right of way is lesser Require greater width for right of
way
Right of entry Right of entry is not free to all vehicles. free and flexible
Suitability to transportation
and goods
For long distances For shorter distances
Gradient Flatter or gentle (not more than 1 in
100)
Steeper gradients up to 1 in 30
Curves Limited up to only 10º Relatively much sharper curves
Suitability of Hilly Regions Not suitable More Suitable
6
Comparison of Railway and Highway
Feature Rail Transport Road Transport
Load handling capacity
Requirement of turning devices
Operation Controls
Employment potential
Rate of accidents
Origin and destinations
Net tons- km per vehicle hour
Construction and maintenance cost
7
Feature Rail Transport Road Transport
Load handling capacity
Requirement of turning devices
Operation Controls
Employment potential
Rate of accidents
Origin and destinations
Net tons- km per vehicle hour
Construction and maintenance cost
7
Comparison of Railway and Highway
Feature Rail Transport Road Transport
Load handling capacity More and that to at high speeds Less and that to low speed
Requirement of turning devices Points and crossings are provided No special devices are required
Operation Controls Require a block system and other
other controls for safe and
efficient movement
No such controls are required
Employment potential more less
Rate of accidents less more
Origin and destinations Fixed Flexible
Net tons- km per vehicle hour Net tons- km per vehicle hour is
higher
Net tons- km per vehicle hour
is lower
Construction and maintenance cost more less
8
Feature Rail Transport Road Transport
Load handling capacity More and that to at high speeds Less and that to low speed
Requirement of turning devices Points and crossings are provided No special devices are required
Operation Controls Require a block system and other
other controls for safe and
efficient movement
No such controls are required
Employment potential more less
Rate of accidents less more
Origin and destinations Fixed Flexible
Net tons- km per vehicle hour Net tons- km per vehicle hour is
higher
Net tons- km per vehicle hour
is lower
Construction and maintenance cost more less
8
Permanent Way
Permanent way is the elements of railway lines: generally the pairs of rails typically laid on the
sleepers embedded in ballast, intended to carry the ordinary trains.
Or
It is the structure consisting of the rails, fasteners, railroad ties (sleepers) and ballast (or slab
track), plus the underlying sub grade.
9
Permanent way is the elements of railway lines: generally the pairs of rails typically laid on the
sleepers embedded in ballast, intended to carry the ordinary trains.
Or
It is the structure consisting of the rails, fasteners, railroad ties (sleepers) and ballast (or slab
track), plus the underlying sub grade.
9
Requirements of an Ideal Permanent Way
1.Gauge should be correct and uniform
2.Rails should be in proper level.
3.Alignment should be correct
4.Gradient should be uniform and as gentle as possible.
5.Track should be resilient and elastic in order to absorb shocks and vibrations.
6.Track should have enough lateral strength.
7.Radii and superelevation on curves should be properly designed and maintained.
8.Drainage system should be perfect for enhancing safety and durability of the track.
10
1.Gauge should be correct and uniform
2.Rails should be in proper level.
3.Alignment should be correct
4.Gradient should be uniform and as gentle as possible.
5.Track should be resilient and elastic in order to absorb shocks and vibrations.
6.Track should have enough lateral strength.
7.Radii and superelevation on curves should be properly designed and maintained.
8.Drainage system should be perfect for enhancing safety and durability of the track.
10
Requirements of an Ideal Permanent Way
9.Various components of the track, i.e., rails, fittings, sleepers, ballast and formation
must fully satisfy the requirements.
10.There should be adequate provision for easy renewals and replacement.
11.Track structure should be strong, low in initial cost as well as maintenance cost.
11
9.Various components of the track, i.e., rails, fittings, sleepers, ballast and formation
must fully satisfy the requirements.
10.There should be adequate provision for easy renewals and replacement.
11.Track structure should be strong, low in initial cost as well as maintenance cost.
11
Gauges
Gauge: Defined as the clear distance between inner faces of two track rails.
Wheel Gauge: Distance between the inner faces of a pair of wheels.
12
Wheel Gauge
Gauge: Defined as the clear distance between inner faces of two track rails.
Wheel Gauge: Distance between the inner faces of a pair of wheels.
12
Wheel Gauge
Different Gauges in India and Abroad
British railways uses a gauge length of 5′ or 1.524m.
Sixty percent of the world's railways use a 4 feet 81⁄2 inch (1435 mm) gauge, which is
known as standard gauge or international gauge.
Rail gauges larger than standard gauge are called broad gauge, and rail gauges smaller
than standard are called narrow gauge.
A dual gauge railway has three or four rails positioned so that trains of two different
gauges can use it.
13
British railways uses a gauge length of 5′ or 1.524m.
Sixty percent of the world's railways use a 4 feet 81⁄2 inch (1435 mm) gauge, which is
known as standard gauge or international gauge.
Rail gauges larger than standard gauge are called broad gauge, and rail gauges smaller
than standard are called narrow gauge.
A dual gauge railway has three or four rails positioned so that trains of two different
gauges can use it.
13
14
https://www.loupiote.com/photos/dual-gauge-tracks-rails-vietnam-96986856.shtml
Dual Gauge System in Vietnam
https://d.indiarailinfo.com/blog/post/1722963
Dual Gauge System, Siliguri Junction, India
https://www.loupiote.com/photos/dual-gauge-tracks-rails-vietnam-96986856.shtml
Dual Gauge System in Vietnam
https://d.indiarailinfo.com/blog/post/1722963
Dual Gauge System, Siliguri Junction, India
Different Gauges in India
East India Company used three different gauges and they are :-
Broad gauge (1676 mm),
Meter gauge (1000 mm),
Narrow gauge (762 mm & 610 mm)
15
East India Company used three different gauges and they are :-
Broad gauge (1676 mm),
Meter gauge (1000 mm),
Narrow gauge (762 mm & 610 mm)
15
Different Gauges in India and Abroad
31.03.2011
16
Type of Gauge Gauge
(mm)
Gauge
(feet)
Route
(km)
% of total length
Countries
Broad Gauge 1676 5′ 6″ 55,188 85.6
Meter Gauge 1000 3′ 3.5″ 6,809 10.6
Narrow Gauge
762 2′ 6″ 2,463 3.8
610 2′ 6″
Total 64,460 100
31.03.2011
16
Type of Gauge Gauge
(mm)
Gauge
(feet)
Route
(km)
% of total length
Countries
Broad Gauge 1676 5′ 6″ 55,188 85.6
Meter Gauge 1000 3′ 3.5″ 6,809 10.6
Narrow Gauge
762 2′ 6″ 2,463 3.8
610 2′ 6″
Total 64,460 100
Various Gauges on World Highways
17
Type of Gauge Gauge
(mm)
Gauge
(feet)
% of total
length
Countries
Standard Gauge 1435 4′8.5″ 62 England, USA, Canada, Turkey,
Persia, and China
Broad Gauge 1676 5′6″ 6 India, Pakistan, Ceylon, Brazil,
Argentina
Broad Gauge 1524 5′0″ 9 Russia, Finland
Cape Gauge 1067 3′6″ 8 Africa, Japan, Australia, and
New Zealand
Meter Gauge 1000 3′3.5″ 9 India, France, Switzerland, and
Argentina
23 Various other
Gauges
Different
Gauges
Different
Gauges
6 Various countries
17
Type of Gauge Gauge
(mm)
Gauge
(feet)
% of total
length
Countries
Standard Gauge 1435 4′8.5″ 62 England, USA, Canada, Turkey,
Persia, and China
Broad Gauge 1676 5′6″ 6 India, Pakistan, Ceylon, Brazil,
Argentina
Broad Gauge 1524 5′0″ 9 Russia, Finland
Cape Gauge 1067 3′6″ 8 Africa, Japan, Australia, and
New Zealand
Meter Gauge 1000 3′3.5″ 9 India, France, Switzerland, and
Argentina
23 Various other
Gauges
Different
Gauges
Different
Gauges
6 Various countries
Selection of Gauges
1.Cost of Construction
2.Volume and Nature of Traffic
3.Development of the Areas
4.Physical Features of the Country
5.Speed of Movement
18
1.Cost of Construction
2.Volume and Nature of Traffic
3.Development of the Areas
4.Physical Features of the Country
5.Speed of Movement
18
Cost of Construction
Marginal increase in the cost of earthwork, rails, sleepers, ballast, and other track items
with gauge.
Cost of station buildings, platforms, signals, bridges, tunnels and culverts etc., is same
more or less for all gauges.
There is little proportional in the acquisition of land.
19
Marginal increase in the cost of earthwork, rails, sleepers, ballast, and other track items
with gauge.
Cost of station buildings, platforms, signals, bridges, tunnels and culverts etc., is same
more or less for all gauges.
There is little proportional in the acquisition of land.
19
Volume and Nature of Traffic
Traffic volume depends upon the size of wagons and the speed and hauling capacity of
the train.
As a wider gauge can carry larger wagons and coaches, it can theoretically carry more traffic.
A wider gauge has a greater potential at higher speeds, because speed is a function of the
diameter of the wheel, which in turn is limited by the width of the gauge.
The type of traction and signalling equipment required are independent of the gauge.
20
Traffic volume depends upon the size of wagons and the speed and hauling capacity of
the train.
As a wider gauge can carry larger wagons and coaches, it can theoretically carry more traffic.
A wider gauge has a greater potential at higher speeds, because speed is a function of the
diameter of the wheel, which in turn is limited by the width of the gauge.
The type of traction and signalling equipment required are independent of the gauge.
20
Development of Areas
Narrow gauges can be used for thinly populated area by joining under developed area with
developed or urbanised area.
Physical Features of the Country
Use of narrow gauge is warranted in hilly regions where broad and meter gauge are not possible
due steep gradients and sharp curves.
Speed of movement
Speed is a function of dia. of wheel, which in turn limited by the gauge. (wheel diameter = 0.75
x Gauge).
21
Narrow gauges can be used for thinly populated area by joining under developed area with
developed or urbanised area.
Physical Features of the Country
Use of narrow gauge is warranted in hilly regions where broad and meter gauge are not possible
due steep gradients and sharp curves.
Speed of movement
Speed is a function of dia. of wheel, which in turn limited by the gauge. (wheel diameter = 0.75
x Gauge).
21
Uniformity of Gauges
Delay cost and hardship in transhipping passengers and goods from the vehicles of one
gauge to another is avoided.
As the transhipping is not required, there is no breakage of goods.
Difficulties in loading and unloading are avoided and labour charges are saved.
Possibility of thefts and misplacement, while changing from one vehicle to another, is
eliminated
Surplus wagons of one gauge cannot be used on another gauges.
22
Delay cost and hardship in transhipping passengers and goods from the vehicles of one
gauge to another is avoided.
As the transhipping is not required, there is no breakage of goods.
Difficulties in loading and unloading are avoided and labour charges are saved.
Possibility of thefts and misplacement, while changing from one vehicle to another, is
eliminated
Surplus wagons of one gauge cannot be used on another gauges.
22
Uniformity of Gauges
Locomotives can be effectively used on all the tracks if uniform type of gauge is
adopted.
Large sheds are not required to store the goods.
Provision of alternate routes
No transport bottlenecks
23
Locomotives can be effectively used on all the tracks if uniform type of gauge is
adopted.
Large sheds are not required to store the goods.
Provision of alternate routes
No transport bottlenecks
23
Coning of Wheels
24
Coning of wheels is mainly done to maintain the
vehicle in the central position with respect to the
track.
Flanges of wheel is never made flat, but they are
in the shape of cone with a slope of 1 in 20.
(Sloping of the wheel from the vertical axis)
24
Coning of wheels is mainly done to maintain the
vehicle in the central position with respect to the
track.
Flanges of wheel is never made flat, but they are
in the shape of cone with a slope of 1 in 20.
(Sloping of the wheel from the vertical axis)
Coning of Wheels
25
25
Advantages of Coning
It helps the vehicle to negotiate a
curve smoothly,
It provides a smooth ride
It reduces the wear and tear of
the wheel flanges.
26
It helps the vehicle to negotiate a
curve smoothly,
It provides a smooth ride
It reduces the wear and tear of
the wheel flanges.
26
Tilting of Rail
To minimize the disadvantages of coning
Rails are tilted inwards
Inclined base plates are used
Slope of base plate is 1 in 20
Advantages
Maintains gauge properly
Wear of the head of rail is uniform due to tilting of rails
Tilting of rails is also known as Adzing of Sleepers
27
To minimize the disadvantages of coning
Rails are tilted inwards
Inclined base plates are used
Slope of base plate is 1 in 20
Advantages
Maintains gauge properly
Wear of the head of rail is uniform due to tilting of rails
Tilting of rails is also known as Adzing of Sleepers
27
Adzing of Sleepers
28
28
Rails
Rails on the track can be considered as steel girders for the purpose of carrying axle
loads.
or
Rails are the members of the track laid in two parallel lines to provide an unchanging,
continuous, and level surface for the movement of trains.
29
Rails on the track can be considered as steel girders for the purpose of carrying axle
loads.
or
Rails are the members of the track laid in two parallel lines to provide an unchanging,
continuous, and level surface for the movement of trains.
29
Functions of Rails
Provide hard, smooth and unchanging surface for the passage of heavy moving loads with
minimum friction steel rails and steel wheels.
Rails bear the stresses developed due to vertical loads, lateral, braking forces, and thermal
stresses.
Rails carry out the function of transmitting the load to a large area of the formation through
sleepers and the ballast.
Rails serve as a lateral guide for the wheels.
Rail material should be such that it gives minimum wear to avoid replacement and failure.
30
Provide hard, smooth and unchanging surface for the passage of heavy moving loads with
minimum friction steel rails and steel wheels.
Rails bear the stresses developed due to vertical loads, lateral, braking forces, and thermal
stresses.
Rails carry out the function of transmitting the load to a large area of the formation through
sleepers and the ballast.
Rails serve as a lateral guide for the wheels.
Rail material should be such that it gives minimum wear to avoid replacement and failure.
30
Composition of Rails
31
For Ordinary Rails
Carbon (C) - 0.55 to 0.68 percent
Manganese (Mn) - 0.65 to 0.9 percent
Silicon (Si) - 0.05 to 0.3 percent
Sulphur (S) – 0.05 percent or below
Phosphorus (P) – 0.06 percent or below
For rails at points and crossings
Carbon (C) - 0.5 to 0.6 percent
Manganese (Mn) - 0.95 to 1.25
percent Silicon (Si) - 0.05 to 0.2 percent
Sulphur (S) – 0.06 percent or below
Phosphorus (P) – 0.06 percent or below
31
For Ordinary Rails
Carbon (C) - 0.55 to 0.68 percent
Manganese (Mn) - 0.65 to 0.9 percent
Silicon (Si) - 0.05 to 0.3 percent
Sulphur (S) – 0.05 percent or below
Phosphorus (P) – 0.06 percent or below
For rails at points and crossings
Carbon (C) - 0.5 to 0.6 percent
Manganese (Mn) - 0.95 to 1.25
percent Silicon (Si) - 0.05 to 0.2 percent
Sulphur (S) – 0.06 percent or below
Phosphorus (P) – 0.06 percent or below
Rail Types
Double Headed (DH) Rails
Bull Headed (BH) Rails
Flat Footed (FF) Rails
32
Double Headed (DH) Rails
Bull Headed (BH) Rails
Flat Footed (FF) Rails
32
Double Headed (DH) Rail
Consists of upper table, web, and lower table
Head and foot of same dimensions
Dumb-bell section
It is first introduced to double the life of rails
But after usage, lower head got dented(eroded)
Smooth running was impossible
33
Consists of upper table, web, and lower table
Head and foot of same dimensions
Dumb-bell section
It is first introduced to double the life of rails
But after usage, lower head got dented(eroded)
Smooth running was impossible
33
34
Bull Headed (BH) Rail
Head of the rail was made a little thicker and
stronger than the lower part by adding more
metal.
Provides smoother and stronger track
Requires costly fastenings.
Rails require heavy maintenance cost.
B.H. rails are of less strength and stiffness.
35
Head of the rail was made a little thicker and
stronger than the lower part by adding more
metal.
Provides smoother and stronger track
Requires costly fastenings.
Rails require heavy maintenance cost.
B.H. rails are of less strength and stiffness.
35
Flat Footed (FF) Rail
These rails are also called as vignole's rails.
Initially the flat footed rails were fixed to the
sleepers directly and no chairs and keys were
required.
Later under heavy loads the foot was found
sinking in the wooden sleeper.
Requires steel bearing plate for load distribution.
Most commonly used in India.
36
These rails are also called as vignole's rails.
Initially the flat footed rails were fixed to the
sleepers directly and no chairs and keys were
required.
Later under heavy loads the foot was found
sinking in the wooden sleeper.
Requires steel bearing plate for load distribution.
Most commonly used in India.
36
37
Comparison of Rail Types
Point of Comparison Flat-footed Rails Bull-headed Rails and Double-
headed Rails
Strength and Stiffness
Laying and Relaying
Arrangements at points,
crossings and at sharp curves
Alignment and stability of
track
Initial Cost
38
Point of Comparison Flat-footed Rails Bull-headed Rails and Double-
headed Rails
Strength and Stiffness
Laying and Relaying
Arrangements at points,
crossings and at sharp curves
Alignment and stability of
track
Initial Cost
38
Comparison of Rail Types
Point of Comparison Flat-footed Rails Bull-headed Rails and Double-
headed Rails
Strength and Stiffness More strength and stiffness Less strength and stiffness
Laying and Relaying Fitting is simple as chairs are not
required
Difficult and time consuming as they
are supported on chairs
Arrangements at points,
crossings and at sharp curves
Simple and easy Complicated and difficult
Alignment and stability of
track
Rolling wheels affects fittings and
loosens it. Disturbs the alignment
and gives less stability.
As it is fitted on chairs, provide a
more solid, smooth track, and better
stable alignment.
Initial Cost Require lesser and cheaper
fastenings, so initial cost is less
Require more and costly fastenings, so
initial cost is more
39
Point of Comparison Flat-footed Rails Bull-headed Rails and Double-
headed Rails
Strength and Stiffness More strength and stiffness Less strength and stiffness
Laying and Relaying Fitting is simple as chairs are not
required
Difficult and time consuming as they
are supported on chairs
Arrangements at points,
crossings and at sharp curves
Simple and easy Complicated and difficult
Alignment and stability of
track
Rolling wheels affects fittings and
loosens it. Disturbs the alignment
and gives less stability.
As it is fitted on chairs, provide a
more solid, smooth track, and better
stable alignment.
Initial Cost Require lesser and cheaper
fastenings, so initial cost is less
Require more and costly fastenings, so
initial cost is more
39
Comparison of Rail Types
Point of Comparison Flat-footed Rails Bull-headed Rails and Double-
headed Rails
Inspection
Maintenance Cost
Replacement of Rails
Suitability
40
Point of Comparison Flat-footed Rails Bull-headed Rails and Double-
headed Rails
Inspection
Maintenance Cost
Replacement of Rails
Suitability
40
Comparison of Rail Types
Point of Comparison Flat-footed Rails Bull-headed Rails and Double-
headed Rails
Inspection Daily inspection is necessary Daily inspection is required
Maintenance Cost Less More
Replacement of Rails Replacement is difficult. Dog spikes
have to be taken out in addition to
fish bolts and fish plates to change
the rail.
Rails can be changed easily by driving
out keys and taking out fish bolts and
fish plates with out disturbing
sleepers.
Suitability More suitable due to better stability,
economy, strength, and stiffness
More suitable when lateral loads are
more important rather than vertical
loads
41
Point of Comparison Flat-footed Rails Bull-headed Rails and Double-
headed Rails
Inspection Daily inspection is necessary Daily inspection is required
Maintenance Cost Less More
Replacement of Rails Replacement is difficult. Dog spikes
have to be taken out in addition to
fish bolts and fish plates to change
the rail.
Rails can be changed easily by driving
out keys and taking out fish bolts and
fish plates with out disturbing
sleepers.
Suitability More suitable due to better stability,
economy, strength, and stiffness
More suitable when lateral loads are
more important rather than vertical
loads
41
Requirements of Rails
Section of the rail should be such that the load of each wheels is transferred to the
sleepers without exceeding the permissible stresses.
Section of the rail should be able to withstand the lateral forces caused due to fast
moving trains.
Bottom of the head and top of the foot of the rail section should be of such a slope
that the fishplates fit snugly.
Web of the rail section should be such that it can safely bear the vertical load without
buckling.
Head of the rail should be sufficiently deep for adequate margin of vertical wear.
Foot of the rail should be wide enough so that the rail is stable against overturning.
42
Section of the rail should be such that the load of each wheels is transferred to the
sleepers without exceeding the permissible stresses.
Section of the rail should be able to withstand the lateral forces caused due to fast
moving trains.
Bottom of the head and top of the foot of the rail section should be of such a slope
that the fishplates fit snugly.
Web of the rail section should be such that it can safely bear the vertical load without
buckling.
Head of the rail should be sufficiently deep for adequate margin of vertical wear.
Foot of the rail should be wide enough so that the rail is stable against overturning.
42
Requirements of Rails
Composition of the steel should conform to the specifications adopted for its
manufacture by Open Hearth or Duplex Process.
Overall height of the rail should be adequate to provide sufficient stiffness and strength
as a simply supported beam.
Centre of gravity of the rail section must lie approximately at mid height of the rail so
that the maximum tensile and compressive stresses are equal.
Tensile strength of the rail piece should not be less than 71 kg/m
2
43
Composition of the steel should conform to the specifications adopted for its
manufacture by Open Hearth or Duplex Process.
Overall height of the rail should be adequate to provide sufficient stiffness and strength
as a simply supported beam.
Centre of gravity of the rail section must lie approximately at mid height of the rail so
that the maximum tensile and compressive stresses are equal.
Tensile strength of the rail piece should not be less than 71 kg/m
2
43
Standard Rail Section
Rail is designated by its weight per unit length.
52 kg/m rail denotes that it has a weight of 52 kg per metre.
The weight of a rail and its section is decided after considerations such as the following:
Heaviest axle load
Maximum permissible speed
Depth of ballast cushion
Type and spacing of sleepers
Other miscellaneous factors
44
Rail is designated by its weight per unit length.
52 kg/m rail denotes that it has a weight of 52 kg per metre.
The weight of a rail and its section is decided after considerations such as the following:
Heaviest axle load
Maximum permissible speed
Depth of ballast cushion
Type and spacing of sleepers
Other miscellaneous factors
44
Standard Rail Section
Usually IR uses 90R rail section for annual traffic density of 10GMT, speeds up to 100
kmph and service life of use about 20 to 25 years.
IR uses two heavier sections (52kg/m and 60 kg/m) on BG line
52kg/m suitable for speed of 130 kmph and traffic density of 20 to 25 GMT.
60kg/m suitable for speed of 160 kmph and traffic density of about 35 GMT.
Wt. of rail/locomotive axle= 1/510
Branding of Rail
IRS–52kg – 880 – SAIL II 1991 → OB
45
Usually IR uses 90R rail section for annual traffic density of 10GMT, speeds up to 100
kmph and service life of use about 20 to 25 years.
IR uses two heavier sections (52kg/m and 60 kg/m) on BG line
52kg/m suitable for speed of 130 kmph and traffic density of 20 to 25 GMT.
60kg/m suitable for speed of 160 kmph and traffic density of about 35 GMT.
Wt. of rail/locomotive axle= 1/510
Branding of Rail
IRS–52kg – 880 – SAIL II 1991 → OB
45
46
Details of Standard Rail Sections
Type of
rail
section
Wt/M Area of
section
(Sq mm)
Dimensions of rail section (mm)
A B C D E F
50R 24.80 3168 104.8 100.0 52.4 9.9 32.9 15.1
60R 29.76 3800 114.3 109.5 57.2 11.1 35.7 16.7
75R 37.13 4737 128.6 122.2 61.9 13.1 39.7 18.7
90R 44.61 5895 142.9 136.5 66.7 13.9 43.7 20.6
52 kg 51.89 6615 156 136.0 67.0 15.5 51.0 29.0
60 kg 60.34 7686 172 150.0 74.3 16.5 51.0 31.5
47
Type of
rail
section
Wt/M Area of
section
(Sq mm)
Dimensions of rail section (mm)
A B C D E F
50R 24.80 3168 104.8 100.0 52.4 9.9 32.9 15.1
60R 29.76 3800 114.3 109.5 57.2 11.1 35.7 16.7
75R 37.13 4737 128.6 122.2 61.9 13.1 39.7 18.7
90R 44.61 5895 142.9 136.5 66.7 13.9 43.7 20.6
52 kg 51.89 6615 156 136.0 67.0 15.5 51.0 29.0
60 kg 60.34 7686 172 150.0 74.3 16.5 51.0 31.5
47
Length of Rails
Longer the rail, the lesser the number of joints and fittings required and the lesser the
cost of construction and maintenance.
Longer rails are economical and provide smooth and comfortable rides.
The length of a rail is, however, restricted due to the following factors.
1.Lack of facilities for transport of longer rails, particularly on curves.
2.Difficulties in manufacturing very long rails.
3.Difficulties in acquiring bigger expansion joints for long rails.
4.Heavy internal thermal stresses in long rails.
IR has standardized a rail length of 13 m (42 ft) for broad gauge and 12 m (39 ft) for
MG and NG tracks.
Indian Railways is also planning to use 26 m, and even longer, rails in its track system.
48
Longer the rail, the lesser the number of joints and fittings required and the lesser the
cost of construction and maintenance.
Longer rails are economical and provide smooth and comfortable rides.
The length of a rail is, however, restricted due to the following factors.
1.Lack of facilities for transport of longer rails, particularly on curves.
2.Difficulties in manufacturing very long rails.
3.Difficulties in acquiring bigger expansion joints for long rails.
4.Heavy internal thermal stresses in long rails.
IR has standardized a rail length of 13 m (42 ft) for broad gauge and 12 m (39 ft) for
MG and NG tracks.
Indian Railways is also planning to use 26 m, and even longer, rails in its track system.
48
Rail Failures
Crushed Heads
Square or Angular Break
Split Heads
Split Web
Flowing Metal in Heads
Horizontal Cracks
49
Crushed Heads
Square or Angular Break
Split Heads
Split Web
Flowing Metal in Heads
Horizontal Cracks
49
Crushed Head
Crushed head means a short length of rail,
which has drooped or sagged across the
width of the rail head.
Crushed heads are due to slipping of wheels
Weak support at the rail end.
50
Crushed head means a short length of rail,
which has drooped or sagged across the
width of the rail head.
Crushed heads are due to slipping of wheels
Weak support at the rail end.
50
Square or Angular Break
Square or Angular Break Flowing Metal in Heads
51
Rail may be completely broken in a
vertical plane or in an inclined plane.
Metal in the rail head is forced to flow
on the sides due to which, the rail
head gets widened and depressed
Square or Angular Break Flowing Metal in Heads
51
Rail may be completely broken in a
vertical plane or in an inclined plane.
Metal in the rail head is forced to flow
on the sides due to which, the rail
head gets widened and depressed
Split Head and Split web
Split head means a split through or near the
middle of the head, and extending into or
through it.
Split web means a lengthwise crack along
the side of the web and extending into or
through it.
52
Split head means a split through or near the
middle of the head, and extending into or
through it.
Split web means a lengthwise crack along
the side of the web and extending into or
through it.
52
Creep of Rails
It is a horizontal or longitudinal movement of rails in a track with respect to sleepers.
It can be minimized but cannot be stopped.
Creep is common to all railway tracks.
The rails in some places, moves by several centimeters in a month.
Creep does not continue in one direction only - tendency to move gradually in the
direction of dominant traffic.
Creep for two rails of the track will not be in equal amount.
55
It is a horizontal or longitudinal movement of rails in a track with respect to sleepers.
It can be minimized but cannot be stopped.
Creep is common to all railway tracks.
The rails in some places, moves by several centimeters in a month.
Creep does not continue in one direction only - tendency to move gradually in the
direction of dominant traffic.
Creep for two rails of the track will not be in equal amount.
55
Creep of Rails
It is a horizontal or longitudinal movement of rails in a track with respect to sleepers.
It can be minimized but cannot be stopped.
Creep is common to all railway tracks.
The rails in some places, moves by several centimeters in a month.
Creep does not continue in one direction only - tendency to move gradually in the
direction of dominant traffic.
Creep for two rails of the track will not be in equal amount.
56
It is a horizontal or longitudinal movement of rails in a track with respect to sleepers.
It can be minimized but cannot be stopped.
Creep is common to all railway tracks.
The rails in some places, moves by several centimeters in a month.
Creep does not continue in one direction only - tendency to move gradually in the
direction of dominant traffic.
Creep for two rails of the track will not be in equal amount.
56
Indication of creep
Closing of expansion
spaces at joints
Marks on flanges and
web of rails made by
spike head, by scraping
or scratching at rail slide.
57
Closing of expansion
spaces at joints
Marks on flanges and
web of rails made by
spike head, by scraping
or scratching at rail slide.
57
Theories of Creep
Wave Action or Wave Theory
Percussion Theory
Drag or Dragging Theory
Starting, Accelerating, Slowing Down (Decelerating) and Stopping of Trains.
Unbalanced Traffic
58
Wave Action or Wave Theory
Percussion Theory
Drag or Dragging Theory
Starting, Accelerating, Slowing Down (Decelerating) and Stopping of Trains.
Unbalanced Traffic
58
Wave Action or Wave Theory
Angular and heavy ballast-
which develops good
interlock
Increased stiffness of track
Lesser sleeper spacing
Bigger section of the rail
59
Angular and heavy ballast-
which develops good
interlock
Increased stiffness of track
Lesser sleeper spacing
Bigger section of the rail
59
Percussion Theory
Due to weak and loose fish bolts
Due to worn out fish plates
Due to loose packing at joints
Due to wide expansion gap
Due to heavy axle loads moving at high speed
60
Due to weak and loose fish bolts
Due to worn out fish plates
Due to loose packing at joints
Due to wide expansion gap
Due to heavy axle loads moving at high speed
60
Drag or Dragging Theory
Backward thrust on driving wheels of locomotive of train push the rail off track
backward.
Other wheel of locomotive and vehicles push the rail in the direction of travel as
explained in Wave Action Theory.
Starting, Accelerating, Slowing Down (Decelerating)
and Stopping of Trains.
Backward thrust of the engine driving wheels push the rails backward when a train is
starting and accelerating.
When slowing down or stop the vehicle braking forces are push the rail forward.
61
Backward thrust on driving wheels of locomotive of train push the rail off track
backward.
Other wheel of locomotive and vehicles push the rail in the direction of travel as
explained in Wave Action Theory.
Starting, Accelerating, Slowing Down (Decelerating)
and Stopping of Trains.
Backward thrust of the engine driving wheels push the rails backward when a train is
starting and accelerating.
When slowing down or stop the vehicle braking forces are push the rail forward.
61
Unbalanced Traffic
a) Single line:
Heavy equal loads pass in both direction, the creep is balanced. If not, creep takes place
in the heavy load direction.
b) Double line:
Since loads are in unidirectional creep occurs in both directions.
62
a) Single line:
Heavy equal loads pass in both direction, the creep is balanced. If not, creep takes place
in the heavy load direction.
b) Double line:
Since loads are in unidirectional creep occurs in both directions.
62
Other Factors
Alignment of Track: Creep is more on curves than on tangent tracks.
Grade of Track: More in case of steep curves, particularly while train moving downward
with heavy loads.
Type of Rails: older rail have more tendency than new one.
Direction of Heaviest Traffic: In heavier load moving direction occurs more creep.
Poor Maintenance of Track Components and Design of superelevation, curves, joints
etc., will also increase the creep
63
Alignment of Track: Creep is more on curves than on tangent tracks.
Grade of Track: More in case of steep curves, particularly while train moving downward
with heavy loads.
Type of Rails: older rail have more tendency than new one.
Direction of Heaviest Traffic: In heavier load moving direction occurs more creep.
Poor Maintenance of Track Components and Design of superelevation, curves, joints
etc., will also increase the creep
63
Effects of Creep
Sleepers move out of square & out of position– affecting gauge & alignment.
Disturbance in gaps get disturbed –expansion gaps widen at some places and close at
others.
Distortion of points and crossings – becomes difficult to maintain the correct gauge
and alignment of the rails at points and crossings.
Effect on interlocking – interlocking mechanism of the points and crossings gets
disturbed by creep.
Difficulty in changing rails – due to operational reasons, it is required that the rail be
changed, the same becomes difficult as new rail is found to be either too short or long.
64
Sleepers move out of square & out of position– affecting gauge & alignment.
Disturbance in gaps get disturbed –expansion gaps widen at some places and close at
others.
Distortion of points and crossings – becomes difficult to maintain the correct gauge
and alignment of the rails at points and crossings.
Effect on interlocking – interlocking mechanism of the points and crossings gets
disturbed by creep.
Difficulty in changing rails – due to operational reasons, it is required that the rail be
changed, the same becomes difficult as new rail is found to be either too short or long.
64
Measurement of Creep
65
65
Rail Joints
Rail Joints are necessary to hold together the adjoining ends of the rails in the correct
position, both in horizontal and vertical plane.
Rail joints are the weakest part in the railway track
Gap of 1.5 to 3mm for expansion
Strength of rail joint is 50% of strength of rail
66
Rail Joints are necessary to hold together the adjoining ends of the rails in the correct
position, both in horizontal and vertical plane.
Rail joints are the weakest part in the railway track
Gap of 1.5 to 3mm for expansion
Strength of rail joint is 50% of strength of rail
66
Requirements of an Ideal Joint
Two rails should be in line – vertically and horizontally
Rail joint should be strong and stiff as the rail itself
Should permit expansion and contraction of rails during temperature changes
Should be easily disconnect able without disturbing whole track
Rail ends shouldn’t get battered(worn out)
Cheap and economical
Require less maintenance
67
Two rails should be in line – vertically and horizontally
Rail joint should be strong and stiff as the rail itself
Should permit expansion and contraction of rails during temperature changes
Should be easily disconnect able without disturbing whole track
Rail ends shouldn’t get battered(worn out)
Cheap and economical
Require less maintenance
67
Types of Rail Joint
1.Suspended joints
2.Supported joints
3.Bridge joints
4.Compromise joint
5.Insulated joint
6.Welded joint
7.Square joints
8.Staggered joints
68
1.Suspended joints
2.Supported joints
3.Bridge joints
4.Compromise joint
5.Insulated joint
6.Welded joint
7.Square joints
8.Staggered joints
68
Types of Joints
Supported Rail Joint Suspended Rail Joint
69
Supported Rail Joint Suspended Rail Joint
69
Types of Joints
Bridge Joint Bridge Joint
70
Bridge Joint Bridge Joint
70
Types of Joints
Compromise Joint Insulated Joint
71
Compromise Joint Insulated Joint
71
Types of Joints
Square Joints Staggered Joint
72
Square Joints Staggered Joint
72
Sleepers
Sleepers are members generally
laid transverse to the rails on
which the rails are supported and
fixed.
73
Sleepers are members generally
laid transverse to the rails on
which the rails are supported and
fixed.
73
Functions of Sleepers
Transfer the load evenly from the rails to a wider area of the ballast
Hold the rails in their correct gauge and alignment
Give a firm and even support to the rails
Act as an elastic medium between the rails and the ballast to absorb the blows and
vibrations caused by moving loads
Provide longitudinal and lateral stability to the permanent way
74
Transfer the load evenly from the rails to a wider area of the ballast
Hold the rails in their correct gauge and alignment
Give a firm and even support to the rails
Act as an elastic medium between the rails and the ballast to absorb the blows and
vibrations caused by moving loads
Provide longitudinal and lateral stability to the permanent way
74
Requirements of an Ideal Sleeper
Initial as well as maintenance cost should be minimum.
Weight of the sleeper should be moderate so that it is convenient to handle.
Designs of the sleeper and the fastenings should be such that it is possible to fix and remove the
rails easily.
Sleeper should have sufficient bearing area so that the ballast under it is not crushed.
Sleeper should be such that it is possible to maintain and adjust the gauge properly.
Design of the sleeper should be such that it is possible to have track circuiting.
75
Initial as well as maintenance cost should be minimum.
Weight of the sleeper should be moderate so that it is convenient to handle.
Designs of the sleeper and the fastenings should be such that it is possible to fix and remove the
rails easily.
Sleeper should have sufficient bearing area so that the ballast under it is not crushed.
Sleeper should be such that it is possible to maintain and adjust the gauge properly.
Design of the sleeper should be such that it is possible to have track circuiting.
75
Requirements of an Ideal Sleeper
Sleeper should be capable of resisting vibrations and shocks caused by the
passage of fast moving trains.
Sleeper should have anti-sabotage and anti-theft features.
76
Sleeper should be capable of resisting vibrations and shocks caused by the
passage of fast moving trains.
Sleeper should have anti-sabotage and anti-theft features.
76
Sleeper Density
Sleeper density is the number of sleepers per rail length.
It is specified as M + x or N + x, where M or N is the length of the rail in metres and x
is a number that varies
Depends on
axle load and speed,
type and section of rails,
type and strength of the sleepers,
type of ballast and ballast cushion, and
nature of formation.
77
Sleeper density is the number of sleepers per rail length.
It is specified as M + x or N + x, where M or N is the length of the rail in metres and x
is a number that varies
Depends on
axle load and speed,
type and section of rails,
type and strength of the sleepers,
type of ballast and ballast cushion, and
nature of formation.
77
Classification of Sleepers
78
Wooden Sleepers
Metal Sleepers
a)Cast Iron Sleepers
b)Steel Sleepers
Concrete Sleepers
Reinforced Concrete Sleepers
Prestressed Concrete Sleepers
78
Wooden Sleepers
Metal Sleepers
a)Cast Iron Sleepers
b)Steel Sleepers
Concrete Sleepers
Reinforced Concrete Sleepers
Prestressed Concrete Sleepers
Timber or Wooden Sleepers
Advantages
Fitting for wooden sleepers are few and simple in design
They have proved very useful for heavy loads and high-speed trains.
They are cheap and easy to manufacture.
They can be handled easily without any damage.
They maintain the correct alignment.
They are most suitable for track circuiting.
They can be used with or without ballast or any type of ballast.
Sleepers are able to resist the shocks and vibrations due to heavy moving loads and also gives less noisy track.
They are suitable in the areas having yielding formations.
79
Advantages
Fitting for wooden sleepers are few and simple in design
They have proved very useful for heavy loads and high-speed trains.
They are cheap and easy to manufacture.
They can be handled easily without any damage.
They maintain the correct alignment.
They are most suitable for track circuiting.
They can be used with or without ballast or any type of ballast.
Sleepers are able to resist the shocks and vibrations due to heavy moving loads and also gives less noisy track.
They are suitable in the areas having yielding formations.
79
Timber or Wooden Sleepers
Disadvantages
Lesser life due to wear, decay, and attack by vermin
Liable to mechanical wear due to beater packing
Difficult to maintain the gauge
Susceptible to fire hazards
Negligible scrap value
Maintenance cost is high compared to other sleepers
80
Disadvantages
Lesser life due to wear, decay, and attack by vermin
Liable to mechanical wear due to beater packing
Difficult to maintain the gauge
Susceptible to fire hazards
Negligible scrap value
Maintenance cost is high compared to other sleepers
80
Types of Timber for Sleepers
Ideal type and universally used they are two categories:
Hard wood sleepers such as Sal, Teak, Kongu etc., and
Soft wood sleepers such as deodar, and chir.
Sal wood is stronger and heavier than teak, while the weight of chir and deodar is about
two-third that of teak and their strength about two-third to three-fourth that of teak.
81
Ideal type and universally used they are two categories:
Hard wood sleepers such as Sal, Teak, Kongu etc., and
Soft wood sleepers such as deodar, and chir.
Sal wood is stronger and heavier than teak, while the weight of chir and deodar is about
two-third that of teak and their strength about two-third to three-fourth that of teak.
81
Steel Sleepers
Advantages
Long life
Easy to maintain gauge and less maintenance problems
Good lateral rigidity
Less damage during handling and transport
Simple manufacturing process
Very good scrap value
Free from decay and attack by vermin
Not susceptible to fire hazards
82
Advantages
Long life
Easy to maintain gauge and less maintenance problems
Good lateral rigidity
Less damage during handling and transport
Simple manufacturing process
Very good scrap value
Free from decay and attack by vermin
Not susceptible to fire hazards
82
Steel Sleepers
Disadvantages
Liable to corrode
Unsuitable for track-circuited areas
Liable to become centre-bound because of slopes at the two ends
Develops cracks on rail seats during service
Design is rail specific
83
Disadvantages
Liable to corrode
Unsuitable for track-circuited areas
Liable to become centre-bound because of slopes at the two ends
Develops cracks on rail seats during service
Design is rail specific
83
Cast Iron Sleepers
Advantages
Less corrosion
Less probability of cracking at rail seat
Easy to manufacture
Higher scrap value
Disadvantages
Gauge maintenance is difficult as tie bars get bent
Provides less lateral stability
Unsuitable for track-circuited lines
Not very suitable for mechanical maintenance and/or MSP because of rounded bottom
Susceptible to breakage
84
Advantages
Less corrosion
Less probability of cracking at rail seat
Easy to manufacture
Higher scrap value
Disadvantages
Gauge maintenance is difficult as tie bars get bent
Provides less lateral stability
Unsuitable for track-circuited lines
Not very suitable for mechanical maintenance and/or MSP because of rounded bottom
Susceptible to breakage
84
Concrete Sleepers
R.C.C and pre-stressed concrete sleepers are now replacing all other types of sleepers
except to some special circumstances such as crossing bridges etc., here timber sleepers
are used.
They were first of all used in France round about in 1914 but are common since 1950.
It may be a single block pre-stressed type.
Concrete sleepers are much heavier than wooden ones, so they resist movement better.
85
R.C.C and pre-stressed concrete sleepers are now replacing all other types of sleepers
except to some special circumstances such as crossing bridges etc., here timber sleepers
are used.
They were first of all used in France round about in 1914 but are common since 1950.
It may be a single block pre-stressed type.
Concrete sleepers are much heavier than wooden ones, so they resist movement better.
85
RCC Sleepers
Advantages
Free from attacks of vermin and decay, suitable for all types of soils
Maximum life of 40 to 60 years
Not affected by moisture, chemical action of ballast, and sub-soil salt
Best suited for modern methods of track maintenance
Higher elastic modulus and hence can withstand the stresses induced by fast and heavy traffic
Elastic fastenings offers an ideal track in respect of gauge, cross-level, and alignment
Most suitable for welded tracks
Prevent buckling more efficiently
Initial cost is high but proves to be economical in long run
86
Advantages
Free from attacks of vermin and decay, suitable for all types of soils
Maximum life of 40 to 60 years
Not affected by moisture, chemical action of ballast, and sub-soil salt
Best suited for modern methods of track maintenance
Higher elastic modulus and hence can withstand the stresses induced by fast and heavy traffic
Elastic fastenings offers an ideal track in respect of gauge, cross-level, and alignment
Most suitable for welded tracks
Prevent buckling more efficiently
Initial cost is high but proves to be economical in long run
86
RCC Sleepers
Disadvantages
Weight of concrete sleeper is as high as 2.5 to 3 times of wooden sleeper.
They damage the bottom edge during packing
Scrap value is almost nil
Heavily damaged at the time of derailment.
87
Disadvantages
Weight of concrete sleeper is as high as 2.5 to 3 times of wooden sleeper.
They damage the bottom edge during packing
Scrap value is almost nil
Heavily damaged at the time of derailment.
87
PSC Sleepers
Maximum permissible compressive strength of 211 kg/cm
2
Minimum compressive strength of concrete in the sleeper is 422 kg/cm
2
at 28 days
The pre-stressed wires are stressed to a initial stress of 8.82 kg/cm
2
Disadvantages
Heavily damaged at the time of derailment.
Bed of ballast is specially prepared.
They are uneconomical
Standard maintenance for the track, where these sleepers are used, is to be kept very high.
88
Maximum permissible compressive strength of 211 kg/cm
2
Minimum compressive strength of concrete in the sleeper is 422 kg/cm
2
at 28 days
The pre-stressed wires are stressed to a initial stress of 8.82 kg/cm
2
Disadvantages
Heavily damaged at the time of derailment.
Bed of ballast is specially prepared.
They are uneconomical
Standard maintenance for the track, where these sleepers are used, is to be kept very high.
88
Comparison of Different Sleepers
Point of
Comparison
Wooden Sleeper CI Sleeper Steel Sleeper Concrete Sleeper
Cost per Sleeper Low Medium High Depends on Design
Life 10 to 15 years for
untreated sleepers; 20
to 25 year for treated
sleepers
35 to 50 years 35 to 50 years
40 to 60 years
Weight of sleeper for
BG (kg)
83 87 79 267
Maintenance Cost High moderate Moderate Low
Handling Manual Manual Manual Mechanical
Track elasticity Good Good Good Best
91
Point of
Comparison
Wooden Sleeper CI Sleeper Steel Sleeper Concrete Sleeper
Cost per Sleeper Low Medium High Depends on Design
Life 10 to 15 years for
untreated sleepers; 20
to 25 year for treated
sleepers
35 to 50 years 35 to 50 years
40 to 60 years
Weight of sleeper for
BG (kg)
83 87 79 267
Maintenance Cost High moderate Moderate Low
Handling Manual Manual Manual Mechanical
Track elasticity Good Good Good Best
91
Comparison of Different Sleepers
92
Point of
Comparison
Wooden Sleeper CI Sleeper Steel Sleeper Concrete Sleeper
Creep Excessive Less Less Minimum
Scrap Value Less High Higher than wood None
Laying and Relaying Easy Difficult due to large
fittings
Easy due to light
weight
Difficult with labor
and Easy with
mechanical devices
Track fittings Less More Less Less
Damage by White ant
and corrosion
Damage by white ants Damage by Corrosion Corrosion is possible
None
Track Circuiting Best Difficult Difficult Easy
92
Point of
Comparison
Wooden Sleeper CI Sleeper Steel Sleeper Concrete Sleeper
Creep Excessive Less Less Minimum
Scrap Value Less High Higher than wood None
Laying and Relaying Easy Difficult due to large
fittings
Easy due to light
weight
Difficult with labor
and Easy with
mechanical devices
Track fittings Less More Less Less
Damage by White ant
and corrosion
Damage by white ants Damage by Corrosion Corrosion is possible
None
Track Circuiting Best Difficult Difficult Easy
Ballast
Ballast is a layer of broken stones, gravel,
moorum, or any other granular material
placed and packed below and around
sleepers for distributing load from the
sleepers to the formation.
It provides drainage as well as longitudinal
and lateral stability to the track.
93
Ballast is a layer of broken stones, gravel,
moorum, or any other granular material
placed and packed below and around
sleepers for distributing load from the
sleepers to the formation.
It provides drainage as well as longitudinal
and lateral stability to the track.
93
Functions of Ballast
It transmits and distributes the moving load of the trains from the sleepers to the
formation uniformly.
It provides a hard and level bed for the sleepers.
It holds the sleepers in proper position during the passage of moving trains.
It provides to some extent an elastic bed for the track.
It protects the formation surface from direct exposure to sun, rain and frost.
It provides a proper drainage to the track, keeping the sleepers in dry condition.
94
It transmits and distributes the moving load of the trains from the sleepers to the
formation uniformly.
It provides a hard and level bed for the sleepers.
It holds the sleepers in proper position during the passage of moving trains.
It provides to some extent an elastic bed for the track.
It protects the formation surface from direct exposure to sun, rain and frost.
It provides a proper drainage to the track, keeping the sleepers in dry condition.
94
Functions of Ballast
It obstructs the growth of vegetation at the track formation.
It provides proper super elevation to the outer rail on curves.
It provides an easy means for correcting the unevenness of the track.
It provides the lateral and longitudinal stability to the track
It protects the sleepers from capillary moisture of formation.
95
It obstructs the growth of vegetation at the track formation.
It provides proper super elevation to the outer rail on curves.
It provides an easy means for correcting the unevenness of the track.
It provides the lateral and longitudinal stability to the track
It protects the sleepers from capillary moisture of formation.
95
Requirements of Good Ballast
It should resist crushing under dynamic loads.
The designed depth of the ballast should be able to distribute the weight of passing trains on the
formation underneath uniformly.
It should not make the track dusty due to powder formation under dynamic wheel loads.
It should be reasonably elastic.
It should have resistance to abrasion and weathering
It should be non-porous to provide durability to the ballast.
It should hold the sleepers laterally and longitudinally under all conditions traffic, especially on
the curves.
It should be able to facilitate easy drainage to rain water
96
It should resist crushing under dynamic loads.
The designed depth of the ballast should be able to distribute the weight of passing trains on the
formation underneath uniformly.
It should not make the track dusty due to powder formation under dynamic wheel loads.
It should be reasonably elastic.
It should have resistance to abrasion and weathering
It should be non-porous to provide durability to the ballast.
It should hold the sleepers laterally and longitudinally under all conditions traffic, especially on
the curves.
It should be able to facilitate easy drainage to rain water
96
Requirements of Good Ballast
It should not produce any chemical action with rail and metal sleepers
Size of ballast should be 5cm for wooden sleepers, 4 cm for metal sleepers and 2.5cm
for turnouts and crossovers
97
It should not produce any chemical action with rail and metal sleepers
Size of ballast should be 5cm for wooden sleepers, 4 cm for metal sleepers and 2.5cm
for turnouts and crossovers
97
Types of Ballast
1.Broken stones
2.Cinder (or ash)
3.Gravels
4.Sand
5.Moorum
6.Over burnt bricks
7.Kankar
98
1.Broken stones
2.Cinder (or ash)
3.Gravels
4.Sand
5.Moorum
6.Over burnt bricks
7.Kankar
98
Broken Stone
Best material for railway track.
Due to high interlocking action it
holds the track to the correct
alignment and gradient
Granite, Quartzite, hard stones, lime
stones are some of the varieties of
stones
For stability graded broken stone is
better than ungraded one.
Graded stone of 50.8mm to 19mm is
found to provide maximum stability
99
Best material for railway track.
Due to high interlocking action it
holds the track to the correct
alignment and gradient
Granite, Quartzite, hard stones, lime
stones are some of the varieties of
stones
For stability graded broken stone is
better than ungraded one.
Graded stone of 50.8mm to 19mm is
found to provide maximum stability
99
Gravel or River Pebbles or Shingle
Obtained from river beds or pits
Cheaper than broken stone
Has excellent drainage property
Requires screening before use
The process of ramming the ballast underneath the sleeper is known as “packing”
The ballast above this layer which surrounds the sleeper, is filled and know as
“Boxing”
The loose ballast between the two adjacent sleepers is known as “Ballast Crib”
100
Obtained from river beds or pits
Cheaper than broken stone
Has excellent drainage property
Requires screening before use
The process of ramming the ballast underneath the sleeper is known as “packing”
The ballast above this layer which surrounds the sleeper, is filled and know as
“Boxing”
The loose ballast between the two adjacent sleepers is known as “Ballast Crib”
100
Ashes or Cinders
Residue obtained from coal used in
locomotives is cinder
It is very cheap and easily available.
Has good drainage property
It is normally used in yards and
sidings or as the initial ballast in
new constructions
Corrosive property
Should not be used where steel
sleepers are used
101
Residue obtained from coal used in
locomotives is cinder
It is very cheap and easily available.
Has good drainage property
It is normally used in yards and
sidings or as the initial ballast in
new constructions
Corrosive property
Should not be used where steel
sleepers are used
101
Sand
Best materials for ballast
It is cheap and provide good
drainage property
Gives silent track
Good for packing of cast iron
pot sleepers
Drawback of sand is its
blowing effect due to vibration
Used on narrow gauge tracks
102
Best materials for ballast
It is cheap and provide good
drainage property
Gives silent track
Good for packing of cast iron
pot sleepers
Drawback of sand is its
blowing effect due to vibration
Used on narrow gauge tracks
102
Moorum
Decomposed laterite rocks
Red in colour or sometimes yellow in colour
Under heavy loads crumbles to powder
Used in sidings and embankments
As it prevents water from percolating into the formation, it is also used as a
blanketing material for black cotton soil.
103
Decomposed laterite rocks
Red in colour or sometimes yellow in colour
Under heavy loads crumbles to powder
Used in sidings and embankments
As it prevents water from percolating into the formation, it is also used as a
blanketing material for black cotton soil.
103
Kankar
It is lime agglomerate which is common in certain clayey soils and is dug out of
ground.
Soft in nature and reduces to powder under loads
Useful for metre gauge and narrow gauge tracks with light traffic
Brick Ballast
Over burnt bricks are broken into small sizes and used
Fairly good drainage
It powders easily and produces dusty track
Corrosive property
104
It is lime agglomerate which is common in certain clayey soils and is dug out of
ground.
Soft in nature and reduces to powder under loads
Useful for metre gauge and narrow gauge tracks with light traffic
Brick Ballast
Over burnt bricks are broken into small sizes and used
Fairly good drainage
It powders easily and produces dusty track
Corrosive property
104
105
Size of Ballast
The size of ballast used varies from 1.9 cm to 5.1 cm.
The best ballast is that which contains stones varying in size from 1.9 cm to 5.1 cm with
reasonable proportion of intermediate sizes.
The exact size of the ballast depends upon the type of sleeper used and location of the track as
below
Ballast size for wooden sleeper tracks = 5.1cm
Ballast size for steel sleeper tracks = 3.8cm
Ballast size for under switches and crossings = 2.54cm
106
The size of ballast used varies from 1.9 cm to 5.1 cm.
The best ballast is that which contains stones varying in size from 1.9 cm to 5.1 cm with
reasonable proportion of intermediate sizes.
The exact size of the ballast depends upon the type of sleeper used and location of the track as
below
Ballast size for wooden sleeper tracks = 5.1cm
Ballast size for steel sleeper tracks = 3.8cm
Ballast size for under switches and crossings = 2.54cm
106
Section of Ballast
The section of the ballast layer consist of depth of ballast under the sleepers & the
width of the ballast layer.
The depth of the ballast under the sleepers is an important factor in the load bearing
capacity & uniformity of distribution of load.
The width of the ballast layer is also important as the lateral strength of track depends
partly upon the quantity of ballast used at the ends of the sleepers.
107
The section of the ballast layer consist of depth of ballast under the sleepers & the
width of the ballast layer.
The depth of the ballast under the sleepers is an important factor in the load bearing
capacity & uniformity of distribution of load.
The width of the ballast layer is also important as the lateral strength of track depends
partly upon the quantity of ballast used at the ends of the sleepers.
107
Ballast Depth
Minimum depth of ballast = 1/2 (c/c Sleepers Spacing – Width of sleepers).
108
Minimum depth of ballast = 1/2 (c/c Sleepers Spacing – Width of sleepers).
108
Ballast Depth
109
109
Forces Acting on the Track
A rail is subjected to heavy stresses due to the following types of forces.
Vertical loads consisting of dead loads, dynamic augment of loads including the effect of speed,
the hammer blow effect, the inertia of reciprocating masses, etc.
Lateral forces due to the movement of live loads, eccentric vertical loading, shunting of
locomotives, etc.
Longitudinal forces due to tractive effort and braking forces, thermal forces, etc.
Contact stresses due to wheel and rail contact.
Stresses due to surface defects such as flat spots on wheels, etc.
110
A rail is subjected to heavy stresses due to the following types of forces.
Vertical loads consisting of dead loads, dynamic augment of loads including the effect of speed,
the hammer blow effect, the inertia of reciprocating masses, etc.
Lateral forces due to the movement of live loads, eccentric vertical loading, shunting of
locomotives, etc.
Longitudinal forces due to tractive effort and braking forces, thermal forces, etc.
Contact stresses due to wheel and rail contact.
Stresses due to surface defects such as flat spots on wheels, etc.
110
Locomotives and Other Rolling Stock
The locomotive is a powerhouse mounted on a frame that produces the motive power
needed for traction on railways.
There are three distinct locomotives used on the railways, each drawing its power from a
different energy source.
There are three types of traction on Indian Railways.
1. Steam traction by steam locomotives
2.Diesel traction by diesel locomotives
3.Electric traction by electric locomotives
111
The locomotive is a powerhouse mounted on a frame that produces the motive power
needed for traction on railways.
There are three distinct locomotives used on the railways, each drawing its power from a
different energy source.
There are three types of traction on Indian Railways.
1. Steam traction by steam locomotives
2.Diesel traction by diesel locomotives
3.Electric traction by electric locomotives
111
112
In a steam locomotive, the motive power is the steam generated in a pressure vessel called the
boiler. Thus the thermal energy of fuel is converted into the mechanical energy of motion.
In a diesel locomotive, the motive power is an internal combustion engine, which uses high-
speed diesel oil as its source of energy.
An electric locomotive derives its power from an electric conductor running along the track.
Diesel and electric locomotives are comparatively more efficient than steam locomotives.
They have greater hauling capacity, permit better acceleration and deceleration, and are capable
of carrying heavy loads at higher speeds.
In a steam locomotive, the motive power is the steam generated in a pressure vessel called the
boiler. Thus the thermal energy of fuel is converted into the mechanical energy of motion.
In a diesel locomotive, the motive power is an internal combustion engine, which uses high-
speed diesel oil as its source of energy.
An electric locomotive derives its power from an electric conductor running along the track.
Diesel and electric locomotives are comparatively more efficient than steam locomotives.
They have greater hauling capacity, permit better acceleration and deceleration, and are capable
of carrying heavy loads at higher speeds.
113
Diesel Locomotive
The diesel locomotive works on the principle of a diesel engine.
It uses diesel oil as fuel and combustion takes places inside a cylinder.
The diesel engine mostly comprises of four-stroke cycles consisting of suction,
compression, ignition, and exhaust.
The energy thus generated is utilized for driving the locomotive.
The horse power generated in a diesel locomotive is transmitted to its wheels in the
following manner
1.Mechanical transmission in the case of conventional diesel locomotives
2.Hydraulic transmission in the case of diesel-hydraulic locomotives
3.Electric transmission in the case of diesel-electric locomotives.
114
The diesel locomotive works on the principle of a diesel engine.
It uses diesel oil as fuel and combustion takes places inside a cylinder.
The diesel engine mostly comprises of four-stroke cycles consisting of suction,
compression, ignition, and exhaust.
The energy thus generated is utilized for driving the locomotive.
The horse power generated in a diesel locomotive is transmitted to its wheels in the
following manner
1.Mechanical transmission in the case of conventional diesel locomotives
2.Hydraulic transmission in the case of diesel-hydraulic locomotives
3.Electric transmission in the case of diesel-electric locomotives.
114
Electric Locomotive
In electric locomotives, movement is brought about by means of electric motors.
These motors draw power from an overhead distribution system through pantographs
(joined frameworks conveying current to an electric train from overhead wines) mounted
on the locomotives.
There are different systems for feeding power to these locomotives, namely 1500-V dc,
750-V dc, 25-kV ac single- phase, and ac three-phase.
115
In electric locomotives, movement is brought about by means of electric motors.
These motors draw power from an overhead distribution system through pantographs
(joined frameworks conveying current to an electric train from overhead wines) mounted
on the locomotives.
There are different systems for feeding power to these locomotives, namely 1500-V dc,
750-V dc, 25-kV ac single- phase, and ac three-phase.
115
Rolling Stock
Rolling stock includes locomotives, passenger coaches, goods wagons, and all other types
of coaches and wagons such as electric multiple units (EMUs), diesel rail cars, and
special wagons such as BOX wagons.
116
Rolling stock includes locomotives, passenger coaches, goods wagons, and all other types
of coaches and wagons such as electric multiple units (EMUs), diesel rail cars, and
special wagons such as BOX wagons.
116
Coaching Stock
The different types of passenger coaches include the electric multiple units that
are a part of suburban trains and conventional coaches such as II class, I class, II
sleeper, ac three tier, ac two tier, and ac I class coaches.
These coaches have three basic structural designs.
Integral coaches built by the Integral Coach Factory (ICF), Perambur, Chennai
Integral coaches built by Bharat Earth Movers Ltd (BEML), Bangalore
Non-integral wooden body coaches made in accordance with the Indian Railways
standard design (IRS)
117
The different types of passenger coaches include the electric multiple units that
are a part of suburban trains and conventional coaches such as II class, I class, II
sleeper, ac three tier, ac two tier, and ac I class coaches.
These coaches have three basic structural designs.
Integral coaches built by the Integral Coach Factory (ICF), Perambur, Chennai
Integral coaches built by Bharat Earth Movers Ltd (BEML), Bangalore
Non-integral wooden body coaches made in accordance with the Indian Railways
standard design (IRS)
117
Goods Wagon
Goods wagons are primarily meant for the carriage of goods traffic.
Indian Railways presently has a stock of about 0.29 million goods wagons with a haulage
capacity of about 10 million t.
These goods wagons mostly consist of covered and open wagons as well as special
wagons such as BOX wagons for carrying coal and other bulk traffic.
The standard wagon on the broad gauge was a four wheeler with a 22.19 t haulage
capacity, while the standard wagon on the metre gauge weighed 5.69 t and had the
capacity of carrying 18.69 t of goods.
Recently, a number of new bogie wagons have been designed and put into service, which
lay emphasis on a higher payload and on the provision of facilities for the loading and
unloading of special type of traffic.
118
Goods wagons are primarily meant for the carriage of goods traffic.
Indian Railways presently has a stock of about 0.29 million goods wagons with a haulage
capacity of about 10 million t.
These goods wagons mostly consist of covered and open wagons as well as special
wagons such as BOX wagons for carrying coal and other bulk traffic.
The standard wagon on the broad gauge was a four wheeler with a 22.19 t haulage
capacity, while the standard wagon on the metre gauge weighed 5.69 t and had the
capacity of carrying 18.69 t of goods.
Recently, a number of new bogie wagons have been designed and put into service, which
lay emphasis on a higher payload and on the provision of facilities for the loading and
unloading of special type of traffic.
118
These include the BOX, BCX,
BOBX, BOY, BOXN, CRT,
wagons, etc. In the above-
mentioned classification of wagons,
B stands for bogie wagon, C for
centre discharge, O for open
wagon, X for high-sided (also for
both centre and side discharge), and
Y for low-sided walls. N is used for
air braked, C for covered wagon, R
for rail-carrying wagon, and T for
transition coupler. The B indication
is sometimes omitted as all new
wagons are bogie stock.
119
BOBX, BOY, BOXN, CRT,
wagons, etc. In the above-
mentioned classification of wagons,
B stands for bogie wagon, C for
centre discharge, O for open
wagon, X for high-sided (also for
both centre and side discharge), and
Y for low-sided walls. N is used for
air braked, C for covered wagon, R
for rail-carrying wagon, and T for
transition coupler. The B indication
is sometimes omitted as all new
wagons are bogie stock.
119
Train Resistance and Tractive Power
Various forces offer resistance to the movement of a train on the track.
1.Resistance due to friction
2.Resistance due to wave action
3.Resistance due to wind
4.Resistance due to gradient
5.Resistance due to curvature
The tractive power of a locomotive should be adequate enough to overcome these
resistances and haul the train at a specified speed.
120
Various forces offer resistance to the movement of a train on the track.
1.Resistance due to friction
2.Resistance due to wave action
3.Resistance due to wind
4.Resistance due to gradient
5.Resistance due to curvature
The tractive power of a locomotive should be adequate enough to overcome these
resistances and haul the train at a specified speed.
120
Resistance due to friction
Resistance due to friction is the resistance offered by the friction between the internal parts of
locomotives and wagons as well as between the metal surface of the rail and the wheel to a train
moving at a constant speed.
Journal friction This is dependent on the type of bearing, the lubricant used, the temperature
and condition of the bearing, etc.
Internal resistance This resistance is consequential to the movement of the various parts of
the locomotive and wagons.
Rolling resistance This occurs due to rail-wheel interaction on account of the movement of
steel wheels on a steel rail.
The total frictional resistance is given by the empirical formula
R1 = 0.0016W
where R1 is the frictional resistance independent of speed and W is the weight of the train in tonnes.
121
Resistance due to friction is the resistance offered by the friction between the internal parts of
locomotives and wagons as well as between the metal surface of the rail and the wheel to a train
moving at a constant speed.
Journal friction This is dependent on the type of bearing, the lubricant used, the temperature
and condition of the bearing, etc.
Internal resistance This resistance is consequential to the movement of the various parts of
the locomotive and wagons.
Rolling resistance This occurs due to rail-wheel interaction on account of the movement of
steel wheels on a steel rail.
The total frictional resistance is given by the empirical formula
R1 = 0.0016W
where R1 is the frictional resistance independent of speed and W is the weight of the train in tonnes.
121
Resistance Due to Wave Action
When a train moves with speed, a certain resistance develops due to the wave action of
the train.
Similarly, track irregularities such as longitudinal unevenness and differences in cross
levels also offer resistance to a moving train. Such resistances are different for different
speeds.
There is no method for the precise calculation of these resistances but the following
formula has been evolved based on experience:
R
2 = 0.00008WV
where R
2 is the resistance due to wave action and track irregularities on account of the speed of
the train, W is the weight of the train in tonnes, and V is the speed of the train in km/h.
122
When a train moves with speed, a certain resistance develops due to the wave action of
the train.
Similarly, track irregularities such as longitudinal unevenness and differences in cross
levels also offer resistance to a moving train. Such resistances are different for different
speeds.
There is no method for the precise calculation of these resistances but the following
formula has been evolved based on experience:
R
2 = 0.00008WV
where R
2 is the resistance due to wave action and track irregularities on account of the speed of
the train, W is the weight of the train in tonnes, and V is the speed of the train in km/h.
122
Resistance Due to Wind
When a vehicle moves with speed, a certain
resistance develops, as the vehicle has to move
forward against the wind.
Wind resistance consists of side resistance, head
resistance, and tail resistance, but its exact
magnitude depends upon the size and shape of the
vehicle, its speed, and wind direction as well as
velocity.
Wind resistance depends upon the exposed area of
the vehicle and the velocity and direction of the
wind.
123
When a vehicle moves with speed, a certain
resistance develops, as the vehicle has to move
forward against the wind.
Wind resistance consists of side resistance, head
resistance, and tail resistance, but its exact
magnitude depends upon the size and shape of the
vehicle, its speed, and wind direction as well as
velocity.
Wind resistance depends upon the exposed area of
the vehicle and the velocity and direction of the
wind.
123
Resistance due to wind
Wind resistance can be obtained by the following formula:
R
3 = 0.000017AV
2
where A is the exposed area of vehicle (m2) and V is the velocity of wind
(km/h).
R
3 = 0.0000006WV
2
where R
3 is the wind resistance in tonnes, V is the velocity of the train in km/h,
and W is the weight of the train in tonnes.
124
Wind resistance can be obtained by the following formula:
R
3 = 0.000017AV
2
where A is the exposed area of vehicle (m2) and V is the velocity of wind
(km/h).
R
3 = 0.0000006WV
2
where R
3 is the wind resistance in tonnes, V is the velocity of the train in km/h,
and W is the weight of the train in tonnes.
124
Resistance Due to Gradient
When a train moves on a rising gradient, it
requires extra effort in order to move
against gravity
125
When a train moves on a rising gradient, it
requires extra effort in order to move
against gravity
125
Resistance Due to Curvature
126
Curve Resistance on BG R
5 = 0.0004WD
Curve Resistance on MG R
5 = 0.0003WD
Curve Resistance on NG R
5 = 0.0002WD
Where W is weight in tonnes and D is
degree of the curve
126
Curve Resistance on BG R
5 = 0.0004WD
Curve Resistance on MG R
5 = 0.0003WD
Curve Resistance on NG R
5 = 0.0002WD
Where W is weight in tonnes and D is
degree of the curve
Tractive Effort of a Locomotive
The tractive effort of a locomotive is the force that the locomotive can generate for
hauling the load.
The tractive effort of a locomotive should be enough for it to haul a train at the
maximum permissible speed.
There are various tractive effort curves available for different locomotives for different
speeds, which enable the computation of the value of tractive effort.
Tractive effort is generally equal to or a little greater than the hauling capacity of the
locomotive.
If the tractive effort is much greater than what is required to haul the train, the wheels
of the locomotive may slip.
127
The tractive effort of a locomotive is the force that the locomotive can generate for
hauling the load.
The tractive effort of a locomotive should be enough for it to haul a train at the
maximum permissible speed.
There are various tractive effort curves available for different locomotives for different
speeds, which enable the computation of the value of tractive effort.
Tractive effort is generally equal to or a little greater than the hauling capacity of the
locomotive.
If the tractive effort is much greater than what is required to haul the train, the wheels
of the locomotive may slip.
127
128
Steam Locomotive
Diesel Locomotive
Electric Locomotive
For an dc electric locomotive: Te = a/V
3
For an ac electric locomotive: Te = a/V
5
Steam Locomotive
Diesel Locomotive
Electric Locomotive
For an dc electric locomotive: Te = a/V
3
For an ac electric locomotive: Te = a/V
5
Hauling Power of a Locomotive
Hauling power of a locomotive depends upon the weight exerted on the driving wheels
and the friction between the driving wheel and the rail.
The coefficient of friction depends upon the speed of the locomotive and the condition
of the rail surface.
The higher the speed of the locomotive, the lower the coefficient of friction, which is
about 0.1 for high speeds and 0.2 for low speeds.
The condition of the rail surface, whether wet or dry, smooth or rough, etc., also plays
an important role in deciding the value of the coefficient of function. If the surface is
very smooth, the coefficient of friction will be very low.
Hauling power = number of pairs of driving wheels × weight exerted on the driving
wheels × coefficient of friction
129
Hauling power of a locomotive depends upon the weight exerted on the driving wheels
and the friction between the driving wheel and the rail.
The coefficient of friction depends upon the speed of the locomotive and the condition
of the rail surface.
The higher the speed of the locomotive, the lower the coefficient of friction, which is
about 0.1 for high speeds and 0.2 for low speeds.
The condition of the rail surface, whether wet or dry, smooth or rough, etc., also plays
an important role in deciding the value of the coefficient of function. If the surface is
very smooth, the coefficient of friction will be very low.
Hauling power = number of pairs of driving wheels × weight exerted on the driving
wheels × coefficient of friction
129
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