Civil Engineering in Indian Railways SPCE

Friday, April 21, 2023SPCE

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Civil Engineering

S S KALRASr. Prof. (Civil Engg), NAIR


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GAUGES ON WORLD RAILWAYSTYPE OF GAUGE

GAUGE IN mm

%OF TOTAL

LENGTH

NAMES OF COUNTRIES

BROAD GAUGE (5’6’’)

1676 6 INDIA, PAKISTAN, SRI LANKA, BRAZIL, ARGENTINA

BROAD GAUGE (5’)

1524 9 RUSSIA, FINLAND

STANDARD GAUGE (4’8.5’’)

1435 62 ENGLAND,USA, CANADA, TURKEY, PERSIA & CHINA

CAPE GAUGE (3’6’’)

1067 8 AFRICA, JAPAN, AUSTRALIA, NEWZEALAND,

METRE GAUGE (3’3.5’’)

1000 9 INDIA, FRANCE, SWITZERLAND, ARGENTINA

VARIOUS OTHER GAUGES

VARIOUS GAUGES

6 INDIA-NARROW GAUGE (762mm & 610mm) – 2’6’’ & 2’)

TOTAL 100


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CLASSIFICATION OF LINES ON INDIAN RAILWAYS

GROUP SPEED POTENTIAL (KMPH)

A 160B 130C SuburbanD 110 and GMT<20

D ‘Spl’ 110 and GMT>20E <110and GMT<5

E ‘Spl’ <110and GMT>5


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MAJOR AREAS OF RESPONSIBILITY

1. PERMANENT WAY

2. WORKS

3. BRIDGES


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PRINCIPAL FEATURES OF PERMANENT-WAY


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Function• Support & guide vehicles running on it

Sleepers

Ballast

Embankment

Rails


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Rails are members of the track laid in two parallel lines to provide continuous surface for the movement of Trains.

Function of rails Provide a continuous and level surface Provide a pathway which is smooth and offers

less friction Lateral guide for the wheels Bear changes due to vertical loads etc. Transfers load to formation through sleepers on

wider area.

RAILS


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BG 60 KG, 52 KG, 90R MG 90R, 75 R, 60R NG 50 R

Rail is Designated by Weight Per Unit Length (Kg/m or Lb/yd) KG- Means Kg/m (Indian Railway Standards) R- Revised British Standards ( Lb/yd)

IRS 52 kg 880 SAIL X10 OB

IRS 52 kg 710 TISCO V 1991 OB

Standard Rail section


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SERVICE LIFE OF RAILS

RAIL SECTION

TOTAL GMT CARRIED, FOR 72 UTS (MM) RAILS

TOTAL GMT CARRIED

FOR 90UTS RAILS

60 KG 550 800

52 KG 350 525

90 R 250 375


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Functions: To Maintain Gauge distance To distributes load over a greater area To provide resilient bed To maintain track to level & line

SLEEPERS


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Wooden -0.3%

Steel- 1.5%

Cast Iron – 4.0%

Pre Stressed Concrete- 94.2%

Fibre Reinforced Plastic

Different Types of Sleepers


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Type Wooden Steel CI PSC

Service life (Yrs) 12-15 40-50 40-50 50-60

Weight(Kg) 33 79 87 267


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Concrete sleepers (PSC)

Advantages(a) Being heavy, tend more strength and stability to the

track and specially suited to LWR(b) With elastic fastening, all along the track to maintain

better gauge, cross level & alignment(c) Being flat bottom, suited for mechanical maintenance(d) Can be used in track circuited areas

Disadvantages(b) Handling and laying difficult(c) Damage at time of derailment(d) No scrap value(e) Not suitable for beater packing


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Elastic fastenings

Requirement of an elastic fastening

1. It should hold the gauge firmly in place2. It should have an adequate toe load3. It should provide sufficient elasticity to absorb the

vibratory shocks4. It should offer adequate lateral resistance.

Grooved Rubber Pads Liners Elastic rail clips MK III


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Different Types of Concrete Sleepers

Normal line sleepers

Points & Crossings

Guard rails

Switch Expansion Joints

Check rail on curves

Level crossings

Dual Gauge


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BALLAST

Sleeper rests on a bed of stones called ‘Ballast’

Functions: Distributes load over a greater area to ‘formation’ Provides elastic & resilient bed Helps to maintain track to level & line Helps in drainage. Longitudinal & lateral stability to track


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REQUIREMENTS OF GOOD BALLAST

Tough and wear resistant Hard to resist abrasion and attrition Non-porous and non-absorbent of water Durable and should not get pulverised due

to weather Cubicle having sharp edges Cheap and economical Size between 20mm – 65mm


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FLAWS IN RAILS/WELDS

Inherent defects Defects due to fault in rolling stock Excessive corrosion Badly maintained joints Defects in weld joints Improper maintenance of track


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ULTRA SONIC FLAW DETECTION OF RAILS

BY TROLLY 2-3 KM/DAY BY SPURT CAR 100-200 KM/DAY

SPURT- SELF PROPELLED ULTRASONIC RAIL TESTING CAR.

SPCE

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SYSTEMS OF TRACK MAINTENANCE

Conventional system From one end - periodic

Directed Track Maintenance (DTM) Need based - as per requirement

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METHODS OF PACKING OF TRACK

Manual (beater) Packing Systematic Through Packing Systematic Overhauling Picking up of slacks

Machine Packing

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MACHINE MAINTENANCE

Necessitated due to Heavier track, difficult to maintain manually.

Damage to Concrete Sleepers due to beater packing

For Uniform Packing

Longer retentivity

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TRACK GEOMETRY

MAIN PARAMETERS Gauge

Alignment

Unevenness- deviation in vertical plane

Cross Level/Twist –out of planeness of one of the four wheels

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METHODS OF MEASUREMENT OF TRACK GEOMETRY.

Manual Track Recording Devices

Microprocessor Based Track Recording Car

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WORKS ON TRACK

Works of routine maintenance Works of short duration Works of long duration

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PROTECTION OF LINE IN CASE OF WORKS OF SHORT DURATION AT STOP DEAD RESTRICTION

DOUBLE LINE SECTION

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PROTECTION OF LINE IN CASE OF WORKS OF SHORT DURATION AT REDUCED SPEED

SAME AS IN CASE OF STOP DEAD RESTRICTION EXCEPT THAT DETONATORS ARE NOT PLACED AND FLAGMAN SHALL LIFT THE FLAG ONLY WHEN DRIVER HAS REDUCED THE SPEED. TRAIN WILL BE HAND SIGNALLED FORWARD

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WORKS OF LONG DURATION

Line blocked by P-Way Inspector in consultation with operating department

Caution order issued by Station Master

Temporary Engineering Signals provided at site by PWI

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PROVIDED AT INTERSECTION OF TWO TRACKS TO PERMIT TRAIN TO PASS FROM ONE TO OTHER.

POINTS AND CROSSINGS

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TURNOUT

AN ARRANGEMENT OF POINTS & CROSSINGS WITH LEAD RAILS BY MEANS OF WHICH ROLLING STOCK IS DIVERTED FROM ONE TRACK TO ANOTHER .

LEFT HAND RIGHT HAND

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LEFT HAND SWITCH, WING RAIL & STOCK RAILS

ON OBSERVER’S LEFT.

RIGHT HAND SWITCH, WING & STOCK RAILS

ON OBSERVER’S RIGHT.

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COMPONENTS OF A TURNOUT

• POINTSTOCK RAILSWITCH RAILSTRETCHER BARS

• CROSSING

CROSSING BODYWING RAILSCHECK RAILS

• LEAD RAILS

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DESIGNS OF SWITCHES

LOOSE HEEL: Tongue rails are joined to lead rails at heel with fish plates

Weak Joint

FIXED HEEL: Tongue rails are held to stock rails at heel by distance blocks & Bolts

Rigid Joint

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SHAPES OF SWITCHES STRAIGHT SWITCH

Tongue rails is straight from the tip of the switch to the heel.

CURVED SWITCH

Tongue rail is curved from the tip to heel to same radius as of turnout.

Permits higher speeds on turnouts.

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CHECK RAIL CLEARANCE:

BG

Min 44 mm

Max 48 mm

MG Min 41 mm

Max 44 mm

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In IRS design, denoted by the co-tangent of the angle

Designated as 1 in N i.e. 1 in 12 crossing will have an angle whose co-tangent is 12.

On Indian Railways 4 sizes are used 1 in 8 ½ 1 in 12 1 in 16 & 1 in 20 ( Flatter Angle - Larger value)

ANGLE OF CROSSING

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BUILT UP CROSSING

4 pieces of rails bent & joined by bolts & blocks

Disadvantage : Not very rigid . Advantage : Cheap.

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One piece cast without Bolts.

Advantages: Better wear resistant Less cost of maintenance

Disadvantage High initial cost

CAST MANGANESE STEEL (CMS) CROSSING

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DIAMOND CROSSING

When one track crosses another at an angle

Comprising of two acute and two obtuse crossings

When required, Train on one track may also be diverted to other track

Made possible by the inclusion of two or four pair of switches with the connecting lead rails

Diamond crossing with slips

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FACTORS LIMITING SPEEDS OVER TURNOUTS

Sudden change in direction of the running edge, at the entry to the switch from a straight track.

Variation in cross level caused by raising of the switch rails.

Absence of super-elevation over the turnout curve.

Non transitioned entry from the curved lead to the straight crossing.

Gaps in the gauge face and running table at the crossing.

Direction and location of the track in horizontal and vertical planes.

Basic requirements –

To serve the purpose of the project – Strategic, Political, Development of backward area, Shortening of existing route, Connecting major trade centers

Economic considerations Aesthetic considerations Maximum safety and comfort

Alignment

Gauge Obligatory points Topography Geological formation Effect of flood Position of road crossings Proximity of labour and material Location of stations Cost considerations Traffic considerations Strategic & Political considerations Overall economy

Factors Affecting Choice of Alignment

Curves are provided on a railway track:

To avoid obstructions

To pass through obligatory points

To have crossings at desired angle with rivers etc.

To develop required length between two points without exceeding prescribed ruling Grade.

Curvature

Horizontal curves – When a change in direction of the track is required.

Vertical curves – Provided at points where two gradients meet and algebraic difference between two grades is equal or more than 0.04 %

Transition curves – is an easement curve, in which the change of radius is progressive throughout its length

Reverse curve

Compound curves

Equilibrium speed – when centrifugal force generated is exactly balanced by cant provided.

Cant deficiency – Difference of cant provided and theoretically required at speed higher than equilibrium speed. Max limit 100 mm on Group A & B and 75 mm on others.

Cant excess – Difference of cant provided and theoretically required at speed lower than equilibrium speed. Max limit on BG is 75 mm.

SUPERELEVATION

B.G. 100 80 with check rails )

M.G. 160 (>140 with check rails )

N.G.( 0.762m) 400

Existing curves are surveyed @ 10 meters apart with the chord of 20 m length

MAXIMUM DEGREE OF CURVATURE

GRADIENT

To negotiate the rise or fall in the level of the railway track

Gradient = h/x (1 in N) = 100h/x (%)

h

x

To connect various stations at different elevations

To provide uniform rise or fall

To follow the natured contours of the ground

To reduce the cost of earthwork

REQUIREMENT OF GRADIENT

1. Ruling gradient

2. Pusher or Helper gradient

3. Momentum gradient

4. Gradients in yards

TYPES OF GRADIENTS

Curves provide extra resistance to movement of trains.

To limit it as on ruling gradient, grade on curve is compensated (flattened) @ –

0.04% per degree of curve on BG 0.03% per degree of curve on MG and 0.02% per degree of curve on NG.

Grade Compensation on Curves

Documents

Civil Engineering in Indian Railways SPCE