BASIC TRANSPORTATION ENGINEERING

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2. Transportation is regarded as an index of economic, social and commercial progress
of the country”.
Modes of Transport
• Land transport
• Water transport
• Air transport
Two major means of land transport are Roads and railways.
INTRODUCTION

3. Advantages of Railways
• Railway have joined people of different castes, religions customs and traditions.
• With adequate network of railway central administration has become easy and
effective
• Role of railway during emergencies in mobilising troops and war equipment has
been very significant.
• Railway have helped in mass migration of people.

4. Social Advantages
• Feeling of isolation has been removed from the inhabitants of Indian villages.
• The social outlook of the masses has been broadened through railway journeys.
• Railway has made it easier to reach religious importance
• Provide safe and convenient mode of transport for the country

5. Economic advantages
• Mobility of people has increased.
• Transport food and clothes during famines.
• Transport raw material to the industries
• Provide employment to millions of people.
• Land values increased due to industrial development.
• Price stabilisation is possible.

6. COMPONTENTS OF RAILWAY TRACK

7.  The high carbon rolled steel sections, which are laid end-to-end. They are fixed to
the sleepers by various fastening and rest on sleepers.
 To provide continuous and leveled surface for the trains to move For carrying
axle loads of the rolling stock
Materials of rails:
Cast – iron
Malleable iron
Wrought iron
steel
Types of rails:
•Double Headed Rail
•Flat Footed Rails
•Bull Headed Rails
RAILS

8. SLEEPER
The members laid transverse under the rails for supporting and fixing them the
gauge distance known as “sleeper”
Functions:
 Supports the rails firmly
 Maintains the uniform gauge on track
 Distributes the weight coming on the rails over a sufficiently large area of
ballast
 Acts as an elastic medium between rails and ballast to absorb vibrations of
trains
 Maintain alignment of the track
 Sleepers also add stability of the permanent way

9. BALLAST
 Layer of broken stones,gravel,moorum or any other granular
material (20-60 mm size) packed below and around sleepers
is known as ballast.
 Provided with side slope - 1.5 :1

10. Functions:
 To provide a hard and smooth surface for the ballast to rest on
 Hold the sleepers in place during the passage of trains
 To transmit and distribute the load from sleepers to formation
 Allow for maintaining correct track levels without disturbing the rail road bed.
 Protect the surface of formation from direct exposure to sun, frost or rain.
 To form an elastic bed
 To drain the water immediately and keep the sleepers in dry condition
 To discourage the growth of vegetation

11. SUB BALLAST
 A layer of moorum, gravel or small aggregate is provided between the ballast and
the earth embankment to drain off the water immediately, its call sub ballast.
EMBANKMENT
 It is also known as the formation, it is provided by levelling the ground &
necessary cutting & filling. The embankment is provided side slope of 1:2.

15. Railway Gauge
The clear horizontal distance between the inner (running)
faces of the two rails forming a track is known as Gauge.
(see in fig given below) This gauge of 1435 mm has been
universally used in Great Britain, France, Germany, U.S.A.,
Canada and most other countries of Europe and is thus
known as the world standard gauge. In India broad gauge
used which has standard size 1676 mm.

16. RAIL GAUGES
The different gauges can broadly be divided into the following
four categories:
1) Broad Gauge:
width 1676 mm to 1524 mm
2) Standard Gauge:
width 1435 mm and 1451 mm
3) Metre Gauge:
width 1067 mm, 1000 mm and 915 mm
4) Narrow Gauge:
width 762 mm and 610 mm
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17. RAIL GAUGES
Following are the factors affecting the choice of a
gauge:
1. Traffic Condition:
If the intensity of traffic on the track is likely to be
more, a gauge wider than the standard gauge is
suitable.
2. Development of Poor Areas:
The narrow gauges are laid in certain parts of the
world to develop a poor area and thus link the
poor area with the outside developed world. 1
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18. RAIL GAUGES
4. Speed of Movement:
 The speed of a train is a function of the diameter
of wheel which in turn is limited by the gauge.
 The wheel diameter is usually about 0.75 times
the gauge width and thus, the speed of a train is
almost proportional to the gauge.
 If higher speeds are to be attained, the B.G track
is preferred to the M.G or N.G track.
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19. RAIL GAUGES
3. Cost of Track:
 The cost of railway track is directly proportional
to the width of its gauge.
 If the fund available is not sufficient to construct
a standard gauge, a metre gauge or a narrow
gauge is preferred rather than to have no
railways at all.
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20. RAIL GAUGES
5. Nature of Country:
 In mountainous country, it is advisable to have a
narrow gauge of the track since it is more
flexible and can be laid to a smaller radius on
the curves.
 This is the main reason why some important
railways, covering thousands of kilometers, are
laid with a gauge as narrow as 610 mm.
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21. Uniformity of Gauges
Gauge to be used in a particular country should be
uniform throughout as far as possible, because it will
avoid many difficulties.

22. Advantage of uniformity of Gauges
 Delay cost and hardship in transferring passengers is avoided
 Transshipping is not require, so no breakage of goods
 Avoided difficulties in loading and unloading
 Possibilities of thefts and misplacement is eliminated
 Labour strikes do not affect the services and operation of train
 Large sheds are not require for storage
 Surplus wagons of one gauge can not be used on another gauge
 Duplication of equipment such as platforms, sanitary
arrangements, etc is avoided
 During military movement, no time is wasting of changing
equipment

23. REQUIREMENTS OF AN IDEAL PERMANENT WAY
The following are the principal requirements of an ideal permanent way or of a good
railway track :-
i. The gauge of the permanent way should be correct and uniform.
ii. The rail should be in proper level in straight portion. Proper amount of super
elevation should be provided to the outer rail above the inner rail on curved portion
of the track.
iii. The permanent way should be sufficiently strong against lateral forces.
iv. The curves, provided in the track, should be properly designed.
v. An even and uniform gradient should be provided through out the length of the
track.
vi. The tractive resistance of the track should be minimum.
vii. The design of the permanent way should be such that the load of the train is
uniformly distributed on both the rails so as to prevent unequal settlement of the
track.

24. viii. All the components parts such as rails, sleepers, ballast, fixtures and fastenings,
etc. should satisfy the design requirements.
ix. All the points and crossings, laid in the permanent way, should be properly
designed and carefully constructed.
x. It should be provided with proper drainage facilities so as to drain off the rain
water quickly away from the track.
xi. It should be provided with safe and strong bridges coming in the alignment of the
track.
xii. It should be so constructed that repairs and renewals of any of its portion can be
carried out without any difficulty.

25. Rails
The rails on the track can be considered as steel girders for the purpose carrying
axle loads. Flat footed rails are mostly used in Indian railways.
Functions of Rails
• Provide hard, smooth and unchanging surface for the passage of heavy moving
loads with minimum friction steel rails and steel wheels.
• The rail material should be such that it gives minimum wear to avoid replacement
and failure.
• Rail transmit loads to the sleepers and consequently reduce pressure on ballast and
formation below.

26. TYPES OF RAIL SECTIONS
• Double headed rails(D.H Rails)
• Bull headed rails(B.H rails)
• Flat footed rails(F.F rails)

28. Weight & length of rails:
Indian railways have standardized flat footed rails for their use on BG, MG, NG. the
types of rail is defined by the weight of rail per meter length.
55 R means the weight of rail is 55 kg/m.
The length of rails used in India are:
BG – 12.80 m, MG – 11.89 m (for BG length is increase 19.2 to 25.6 m)
Sr. No. Gauge Types of rail Weight in Kg/m
1 B.G.
55 R 55
45 R 45
35 R 35
2 M.G.
35 R 35
30 R 30
25 R 25
3 N.G. 25 R 25

29. SLEEPERS
these are members laid transverse to the rails on which rails are supported and fixed
to transfer the loads from rail to ballast and subgrade below.
Functions of sleepers:
▪ To hold the rails to correct gauge.
▪ To act an elastic medium between the ballast and rail to absorb the blows and
vibrations due to moving loads.
▪ To distribute load from the rail to the index area of ballast or to the girders in case of
bridges.
▪ To support rails - at proper level in straight tracks - at proper super elevation on
curves

30. Requirements of sleepers
• Sleeper should be economical i.e, minimum initial and maintenance cost.
• Fitting of the sleepers should be easily adjustable during maintenance operations.
Such as
✓ Lifting
✓ Packing,
✓ Removal and replacements.
✓ The weight of the sleeper should not be too heavy or excessively light i.e. with
moderate weight they should be for ease of handling.
✓ Design of sleepers should be such a way that the gauge and alignment of track
and levels of the rails can easily adjusted and maintained.
✓ The bearing area of sleepers below the rail seat and over the ballast should be
enough to resist the crushing due to rail seat and crushing of ballast under sleepers.
✓ Design and spacing such a way to facilitate easy removal and replacement of
ballast.

31. • Sleepers should be capable of resisting shocks and vibrations due to passage of
heavy loads of high speed trains.
• Sleepers design should be such a way they are not damaged during packing
process.
• Design should be strong enough so that they are not pushed out easily due to the
moving trains especially in case of steel sleepers with rounded ends.
• An ideal sleeper should be anti-sabotage and anti-theft qualities.

32. Types of sleepers
sleepers
Wooden
sleepers
Iron
sleepers
C.I. sleepers
Steel
sleepers
Concreter
sleepers
RCC
sleepers
Pre-stressed
concrete
sleepers

33. Sleeper density
sleeper density is the number of sleepers per rail length
It is specified as (n + x)
where, n = length of rail in meter
x = variable factor
= 1, 2, 3,…..etc.
For instance,
If length of rail is 12.8 m, 17 sleepers are expressed as (n + 4) i.e. (13 m+ 4)
This (n+ 4) is the density of sleepers.
In India, sleeper density varies from (n + 4) to (n + 6).
In Britain, sleeper density is (n + 4),
In USA, sleeper density varies from (n + 9) to in (n + 11).

34. Factors governing sleeper density
1. Axle load and speed
2. Type and section of the rail
3. Type of ballast
4. Type of sleeper, i.e. bearing area of sleeper

35. 2. BALLAST
Ballast is a layer of
broken stone, gravel, or
any other suitable
material placed under
and around the sleepers
for distributing the load
from the sleepers to the
formation

37. Functions of Ballast
 It provides a suitable foundation for the sleepers.
 It transfer and distributes loads from the sleepers to
a larger area of formation.
 it provides effective drainage to the track.
 It helps in protecting the top surface of the
formation.

38. Physical Properties of Good Ballast
 It should be hard and tough.
 It should wear resistant and durable.
 It should be non-porous and non-absorbent of water.
 It should be cheaper and easily available.
 It should not be brittle.
 It should not allow rain water to accumulate

39. Types of ballast
Following materials can be used as ballast:
1. Broken stone
 It is the best material to be used as ballast.
 Generally on all important tracks broken stone ballast has
been used.
 Blast of Igneous rocks is the most suitable
2. Gravel
 It stands second in suitability as ballast.
 Used in large quantities in many countries.
 It is obtained from river beds

40. 3. Cinders
 The residue obtained from the coal used in locomotives
is known as Cinder.
4. Sand
 It stands fourth in merits as ballast material.
 Coarse sand is better than fine sand.
5. Brick ballast
 Where stone or other suitable ballast is not available,
over burnt brick ballast can be used.
6. Kankar
 It is found in the form of particles of varying sizes.
 Where stone is not easily and at reasonable price
available, kankar can be used as road metal and ballast
for railway tracks.

41. Volume of ballast
 For 1 meter length the quantity of ballast required as
below
 B.G. – 1.036 mᶟ
 M.G. – 0.071 mᶟ
 N.G. – 0.053 mᶟ

43. Joints
 To hold together the adjoining ends of rails in the
correct position to ensure continuity. It is weakest
part of the track.
 It is only 50% of the strength of a rail
 Gap is 6 to 15 mm kept between to end of rails
 Sleeper are provided at closer at the end of rail joints
 Joints are eliminated up to 1 km of length of track for
meeting higher speed.

44. Types of Joints
 Types according to position of joints
 Square joints
 Staggered joints
 Types according to position of sleepers
 Suspended joints
 Supported joints
 Bridge joints

45. Types of Joints
 Square joints
 When a joint in one rail is exactly opposite to the
joint in the parallel rail it is called as square joint.
 Very common type of joint in straight track.
 Staggered joints
When a joint in one rail is exactly opposite to the
centre of the parallel rail length it is called as
staggered joint.

47. Types of Joints
 Suspended rail joint:
 When rail ends are projected beyond sleepers it is termed
as suspended joint.
 This type of joint is generally used with timber and steel
through sleepers.
 Supported rail joints:
 When the rail ends rest on a single sleeper it is termed as
supported joint. The duplex joint sleeper with other
sleepers is an example of the supported joint.

48. Types of Joints
 Bridge joints:
 When the rail ends are projected beyond sleepers as
in the case of suspended joint and they are connected
by a flatter corrugated plate called as bridge plate it
is termed as a bridge joint.

50. CONING OF WHEELS
 The distance between the inside edge of wheel
flanges is kept less than the gauge.

51. CONING OF WHEELS
 The Surface of wheels are made in cone shape at an inclination of
1 in 20, and the same slope is provided in the rails (see fig), this
is known as coning of wheels.
 The diameter of wheel is different at different cross section of the
wheel, when the train running on the straight track try to move
in any direction.
 Flat wheels of train would cause shock loads to the sides of the
rails because of lateral movement between wheels and the rails.
 The coning of wheels is mainly done to maintain the vehicle in
the central position with respect to the track.

52. CONING OF WHEELS
 whereas on a curved track, due to centrifugal force
the train is forced in outward direction, the diameter
on outer track increases and the distance on two
tracks are adjusted.
 Purpose:
 To keep the train in its central position of the rails,
coning does not allow any sidewise movement on a
straight track.
 to allow the wheels to move different distances on a
curved track and thereby reduce wear and tear.

53. Advantages of coning the wheels
 Coning the wheels reduces the depreciation of the
wheel rims and rails. Depreciation is caused because
of the friction action of rims with inner faces of the
rail top.
 Coning also gives an option of lateral drift of the
hinge with is wheels.
 Coning also prevents, to some extent, the slipping of
the wheels.

54. ADZING OF SLEEPER
 To provide a cant (slope) of 1 in 20 in the rails, the
wooden sleepers have to be cut to this slope at rail
seat. This process of cutting the wooden sleeper at 1
in 20 is known as adzing of sleeper.
 For concrete or steel sleeper, the top surface of
sleeper is provided with slope of 1 in 20.