Railway Engineering- Basic Introduction

Aman BathlaAman Bathla
(A.P.)(A.P.)

Review of Syllabus
Unit –Unit – II
Part -Part - II

Railway Engineering: Definition
 Railway Engineering is the branch of Civil Engineering which
deals with the design, construction & Maintenancedesign, construction & Maintenance of the
Railway Tracks for safe & efficientsafe & efficient movements of trains is
called Railway Engineering.

Railway Engineering: Importance
 Indian railways carry most of the long distances passengers
traffic & 80% of the total freight.
 Indian railways provide employment to a huge number of the
people in the country.
 Provide mail services.
 They carry big chunks of goods from place of production to
ports.
 Iron & steel industries based upon railways as they transport
raw materials & finished products from one place to another.

Railway Track (Permanent Way)
The combination of rails, fitted on sleepers & resting on ballast and
subgrade is called the Railway Track.

Component: RAILS
 Rails are the steel girderssteel girders which provides the hard &
smooth surface for movement of wheels of locomotive &
Railway vehicles.
 A Rail is designated by weight per unit length which can
be found as per the Locomotive axle load.
Weight of the rail in tonnes 1
Locomotive axle load in tonnes 510
The Rail Sections of 60 kg/m & 52 kg/m are more
economical & have been adopted recently on B.G. tracks on
Indian Railways.

Functions of Rails
 Provide hard, smooth & unchanging surface for passage of
heavy moving loads with a minimum friction between the
steel rails & steel wheels.
 Rails bear the stresses developed due to heavy vertical
loads, lateral & braking forces & thermal stresses.
 The rail material used in such that it gives minimum wear to
avoid replacement charges & failures of rails due to wear.
 Rails transmit the loads to sleepers & consequently reduce
pressure on ballast & formation below.

Composition of Rail Steel
For Ordinary Rails For Rails on Points & Crossings
Carbon 0.55 - 0.68% 0.5 – 0.6%
Manganese 0.65 - 0.90% 0.95 – 1.25%
Silicon 0.05 - 0.3% 0.05 – 0.20%
Sulphur < 0.05% < 0.06%
Phosphorus < 0.06% < 0.06%
High
Carbon steel
Medium
Carbon steel

Requirement of Rails
 Composition of steel should be proper.
 The centre of gravity of the rail section must lie
approximately at mid height so that maximum tensile &tensile &
compressive stressescompressive stresses are equal.
 The head must be sufficiently deep to protect it from wearwear.
 The web must be sufficiently thick to provide flexure rigidityflexure rigidity.
 The foot should be sufficiently wide to resist overturningoverturning.
HeadHead
WebWeb
FootFoot

Types of Rail Sections
 Double headed rails- can be inverted & reused (used earlier)
 Bull headed rails- even after wear, can withstand stresses
 Flat footed rails- pressure will be less on the sleeper (most
commonly used in India)

Selection of Rails
Weight of the Rail

Length of Rails
On Indian Railways the Standard Lengths are 42 ft for B.G. & 39 ft for M.G.

Corrugated or Roaring of Rails
 Due to traction of the wheel of the train roaring Sound is
heard from the rail.
Measure taken to Rectify-
Grinding the Rail Head.

Hogged Rails
 Due to repeated hitting (Battering) action of wheel over the
end of the rails, The Rails get bent down & get deflected at
the ends.
Measures taken to rectify
1)Cropping
2)Replacing
3)Welding
4)De-hogging

Kinks or shoulders in Rails
 Due to Loose packing at joints & defect in gauge, the ends of
adjoining Rails moves slightly out of position.
1)Correcting the alignment at joints
2)Proper packing of joints
3)Proper maintenance of track

Buckling of Rails
 On account of temperature variations, The track has gone
out of its original positions or alignment.
 This is due to prevention of expansion of rails in hot weather.
1)The fish bolt should not be tightened too hard
2)Proper lubrication should be done.
3)Expansion gap should be provided.

Wear on Rails
 Heavy axle load & the fast speed of the train results in wear
& tear of Rails.
 Types of wear of Rails
1)Wear on the head of the Rail
2)Wear at the ends of The Rails
3)Wear on the sides of the head

Wear on Head of Rail
 Metal from the top of rails flows & forms burrs which later get
chipped off.
Causes:
1)Grinding action of dust particles between rail & wheel
2)Constant break application
3)Abrasion of rolling Rails
4)Fluctuation in gradient
5)Corrosion
6)Weak Track

Wear at the Ends of the Rails
1) Loose Fish Plate & bolt
 Due to blowing action of the wheel on the end of the rail as
the wheel jumps on the gap, the ends of the rail get
bettered or wear.
 Much more in magnitude than the wear on the head of the
Rail
Causes:
1) Heavy Load & large joint Openings
2) Difference in Rail level at joints
3) Small wheels

Wear on the sides of the Head
 At curves, flange of outer wheel strikes inside the outer rail
 More than first two types of wears & most destructive in
nature.
Causes:
1)Slipping & skidding of wheels at curves
2)Trains run at lesser speed
3)Rigidity of wheel base

Methods to reduce Wear
 Use special alloy steel
 Regular tightening of fish bolt & Packing of Ballast
 Reduction of No. of Joints
 Correct adzing of Sleepers
 Lubricating he gauge face
 At Curves, The Check rail Parallel to inner Rails can be
introduced.

Creep of Rails
 Longitudinal Movement of rails with respect o the sleepers in
a track
 Common to all railway tracks
 Value changes from 0 to 130mm per months
 Creep IndicatorCreep Indicator used to measure the creep of rails

Creep- Factors determining the
magnitude & direction

 Ballast is the granular materialgranular material packed under & around the
sleepers to transfer loads from sleepers to the ballast.
Component: BALLAST

 Sleepers are the members laid transverselymembers laid transversely under the rails
which are meant to support the rail over them & transfer the
load from rails to ballast.
Component: SLEEPERS

 Track gauge is the minimum distanceminimum distance between the inner
running faces of the two rails.
Component: TRACK GUAGE

Guages In India & Abroad
Type of gauge Gauge width
Standard gauge (B.G.) 1.67 m
Metre gauge (M.G.) 1.0 m
Narrow Gauge (N.G.) 0.762 m
Light Gauge (L.G.) 0.610 m
S. No.S. No. Type of GaugeType of Gauge CountriesCountries
11 Standard Gauge U.K., U.S.A., Canada, etc.
22 Metre Gauge France, Switzerland, etc.
33 Narrow Gauge India, U.K.
44 Light Gauge India & South Africa

Selection of Gauge
 Cost of Construction increases with the gauge width.
 For heavier loads & High speed, wider gauge are selected.
 For developed & under-developed areas narrow gauge are
used.
 Narrow gauge is preferred for Hilly Areas.

Coning of wheels &
Adzing of sleepers
 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, this is known as Coning of Wheels.Coning of Wheels.
 The process of cutting the wooden sleepers & casting the
concrete sleepers to obtain the inward slope of 1 in 20 for
rails, is known as Adzing of Sleepers.Adzing of Sleepers.

Permanent way: Requirements
 Guage should be correct & uniform.
 The Rails should be in proper level.
 The alignment should be correct.
 The gradient is as gentle as possible.
 The radii and super elevation on curves should be properly
designed & maintained.
 Joint should be properly designed & maintained.
 The track structure should have low initial as well as
maintenance cost.

Railway Engineering- Basic Introduction

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