Presentation on Railway Track by

P.P.KumarADEN/PKU

S.E.Railway

Introduction: Railway Track

Load Transfer

Important Functions of Ballast

To transfer and distribute the load form sleepers to a larger area of formation.

To provide elasticity and resilience to track for getting proper riding comfort .

To provide necessary resistance to track for longitudinal lateral stability .

To provide effective drainage to track.

To provide effective means of maintaining evenness and alignment of track

Standard Ballast Profile

Advantage of Traditional Ballasted Track

Advantage• Relatively low construction costs.• High elasticity.• High maintainability at relatively low costs.• High noise absorption.

Disadvantage of Traditional Ballasted Track

Disadvantage• Over time, track tends to ‘float’, in both longitudinal and

lateral direction, as a result of non linear, irreversible behaviour of the materials.

• Limited non-compensated lateral acceleration in curves, due to limited lateral resistance offered by the ballast.

• Ballast can be churned up at high speeds, causing serious damage to the rails and wheels.

• Reduced permeability due to contamination, grinding down of ballast and transfer of fine particles from sub grade.

• Ballast is relatively heavy, leading to an increase in costs of building bridges and viaducts, if they are to carry continuous ballasted track.

• ballasted track is relatively high, this direct consequences on tunnel diameter and access points.

Advantage of Ballastless Track

• Reduced Height • Lower maintenance requirement and hence,

higher availability for train operation• Increased service life• Lack of suitable ballasted material• A requirement for track to cause(even) less

noise and vibration nuisance

• Ballastless tracks are the good options for high speed heavy haul trains; but on the other hands they are costly also.

PRINCIPAL FEATURES OF PERMANENT-WAY

12

Function•Support & guide vehicles running on it

Sleepers

Ballast

Embankment

rails

13

•Conventional Track • Consists of two “Rails” located at a fixed distance apart• Called “Gauge”• The Gauge of a track is the distance between inner edges of the

heads of rails in track, measured at 16mm below the top surface of the rail.

14

Rails

Rails are members of the track laid in two parallel lines to provideon our continuous and land surface for the movement ofTrains.

Function of rails

(a) Provide a continuous and level surface(b) Provide a pathway which is smooth and less friction(c) Lateral guide for the wheels(d) Bear changes due to vertical loads etc.(e) Transfers to formation through sleepers on wider area.

15

16

Coning of wheels – The distance between the inside edges of wheel flanges is generally kept less than the gauge. Gap is about 38 mm on Either side. Normally the tyre is absolutely ahead centre on the head of the rail, as the wheel is coned to keep it in this central position automatically. These wheel are coned at a slope

Theory of coning:- On a level track, as soon as the axle moves towards one rail, the diameter of the wheel tread over the rail increases, while It decreases over the other rail. This prevents to further movement And axle retreats back to its original position ( with equal dia or both rails and equal pressure on both rails).

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• Advantages of coning of the wheels are :-1. To reduce the wheel and tear of wheel flange

and rails which due• To rubbing action of flanges with inside to

cess of the rail head.2. To provide a possibility of lateral movement.

Sleepers

Sleepers are transverse ties that are laid to support the rails. TheyHave an important role in the track as they transmit the wheel loadFrom the rails to the ballast.

Functions and requirement of sleepers(a) Holding the rails to their correct gauge alignment(b) Giving a firm and ever support to the rails(c) Transfering the load evenly from rails to a wider area of the ballast.(d) Providing longitudinal and lateral stability the permanent way.

Sleeper density and spacing of sleepersSleeper density is the number of sleeper per rail length. It is M +XSpecified on where M– length of the rail

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Sleeper Density

• M+4 low density traffic < 10 GMT & D & E routes

• M+7– M is the rail length for 13 m rail length M+7 =20

• For Long Welded Track 1540 sleepers per Km or 1660 sleepers per Km

20

Concrete Sleeper

Pre-Stressed Concrete Sleeper (PSC)

21

REQUIREMENT OF SLEEPER

• IT SHOULD PROVIDE EASY MEANS OF MAINTAINABILITY

• HANDLING OF RAILS, SLEEPER & FASTENING SHOULD BE EASY

• QUICK RESTORATION AFTER ACCIDENT IS POSSIBLE

• MATERIAL AND DESIGN IS AVAILABLE

• IT SHOULD HAVE ANTI THEFT AND ANTI-SABOTAGE QUALITY

• IT SHOULD BE OVERALL CHEAP

LOAD DISTRIBUTION FROM AXLE TO SLEEPERS

DESIGN CONSIDERATIONS

• THE REACTION AT THE RAIL SEAT DEPENDS UPON------- – SLEEPERS SPACING – AXLE LOADS– SPEED OF TRAINS– THE STANDARD OF MAINTENANCE OF TRACK

DESIGN CONSIDERATIONS

• TO CALCULATE THE FORCES TO WHICH THE CONCRETE SLEEPERS ARE SUBJECTED IS COMPLICATED AND IS GENERALLY BASED ON OBSERVATIONS, EXPERIENCE AND MEASUREMENTS.

DESIGN CONSIDERATIONS

• FOR BG (22T AXLE LOAD), A WHEEL LOAD OF 11 T AT THE RAIL TOP WILL CAUSE A VERTICAL SLEEPER REACTION OF 6 T.

• FOR MG (14T AXLE LOAD), THIS VALUE IS 5 T. THESE LOADS ARE AUGMENTED BY 150% TO CATER

FOR DYNAMIC AUGMENT FOR DESIGN PURPOSE.

CONDITION NO. 1 NO CENTRE BINDING

1040 MM 1040 MM

670MM

15 TONNE 15 TONNE

1750 MM

p

CONDITION NO. 2 WITH CENTRE BINDING

1040 MM 1040 MM

670MM

15 TONNE 15 TONNE

1750 MM

p’p’

CONDITION NO. 3 : Lateral load

13 TONNE

1750 MM

p

7 TONNE

DESIGN CONSIDERATIONSB

.M.

1.237CONDITION 2

CONDITION 3

CONDITION 11.277

DESIGN CONSIDERATIONS

• MAX. B.M. AT RAIL SEAT IS GOVERNED BY CONDITION NO.1

• MAX. B.M. AT CENTRE IS GOVERNED BY CONDITION NO.2

• CONDITION NO.3 DOES NOT GOVERN THE MAX. B.M. AT ANY LOCATION AND HENCE IS NOT CONSIDERED

SHAPE OF SLEEPER IN PLAN –

– SHOULD NOT ALLOW CONCENTRATION OF THE BALLAST REACTION IN MIDDLE

HENCE TRAPEZOIDAL SHAPE

ADDITIONAL LATERAL RESISTANCE DUE TO WEDGING ACTION

• SLEEPER PROFILE IS TRAPEZOIDAL BECAUSE IT IS HAVING MORE SECTION MODULUS

COMPARED TO RECTANGULAR SECTIONS WITH SAME CROSS SECTIONAL AREA.

IT ALSO FECILITATE EASY DEMOULDING AND MORE ROOM FOR HTS WIRES AT THE BOTTOM.

SHAPE OF SLEEPER IN PLAN

ADVANTAGES OF PSC SLEEPERS

• HEAVY WEIGHT--PROVIDES LONGITUDINAL & LATERAL STABILITY REQUIRED FOR LWR

• WITH ELASTIC FASTENING, IT CAN MAINTAIN GAUGE AND ALIGNMENT PROPERLY, HENCE MORE SAFE

• FLAT BOTTOM –SUITES MECH. TAMPING• COST EFFECTIVE• DURABLE--IMMUNE TO TERMITE, FIRE, RUSTS, ETC.• ANTI THEFT & ANTI-SABOTAGE• SUITED FOR TRACK CIRCUITING

DISADVANTAGES OF PSC SLEEPERS

LAYING & HANDLING IS DIFFICULT AS IT IS HEAVYDIFFICULT TO RESTORE TRAFFIC AFTER ACCIDENTNOT AMENABLE TO MANUAL LAYING OR MAINT.REQUIRES MORE BALLAST AND WIDER FORMATIONNO SCRAP VALUE- DIFFICULT TO DISPOSEMAINTENANCE OF JOINT IS DIFFICULTNOT UNIVERSAL --USE OF DIFF. TYPE OF SLEEPERS

FUNCTIONS OF SLEEPER ASSEMBALY

• TRANSMIT AXLE LOAD OF VEHICLES TO BALLAST PROPERLY

• HOLD – GAUGE– LEVEL– ALIGNMENT

• PROVIDING LONGITUDINAL & LATERAL STABILITY TO TRACK

Fishplate

– To provide continuity across rail joint for the movement of railway vehicles

– Rail ends are connected by “fishplates” & “fish bolt”

37

FASTENINGS

• Fixing arrangement for Rails and sleepers

• Various types • Depending on

type of Rails & Sleepers,

38

FASTENING

• UIC ORE DEFINITION– FASTENINGS OR FASTENING DEVICES ARE DESIGNED AS

THAT ASSEMBLY OF PARTS , ENSURING THE CONNECTION BETWEEN RAILS AND SLEEPERS OR RAIL BEARERS IN THE CASE OF TRADITIONAL TRACK LAYING SYSTEM OR WITH SUBSTRUCTURE IN CASE THE TRACK IS LAID DIRECTLY ON THE STRUCTURES OR ON THE TUNNEL BASE.

• VARIOUS TYPES–RAIL FREE–RIGID–ELASTIC

FASTENING TYPES

• FORCES IN TRACK– DOWNWARD FORCES: SLEEPER UNDER

LOAD,THERE WILL BE A TENDENCY OF GAP BETWEEN RAIL AND FASTENING - FASTENING PREVENTS THIS

– UPWARD FORCES: LOAD AWAY FROM SLEEPER, TRACK TENDS TO LIFT UPWARD,GAP BETWEEN RAIL AND SLEEPER – FASTENING PREVENT THIS

FASTENING (FORCES)

FASTENING (FORCES)

– ROTATION OF SLEEPERS: ROTATION OF SLEEPERS ABOUT ITS OWN AXIS - FASTENING TO PREVENT THIS

– LATERAL FORCES: DUE TO PARASITIC MOTIONS AND DUE TO LONGITUDINAL COMPRESSION(DURING BUCKLING)– RAIL HAS TENDENCY TO MOVE LATERALLY ON SLEEPER AND SOMETIME COMPLETE TRACK MOVE LATERALLY-FASTENING SHOULD PROVIDE BUCKLING STRENGTH AND TORSIONAL STRENGTH

• LONGITUDINAL FORCES: CAUSED BY THERMAL STRESSES,WAVE ACTION AND ADHESION BETWEEN RAIL AND WHEEL.THESE FORCES MAY CAUSE MOVEMENT OF RAIL OVER SLEEPER OR MOVEMENT OF ENTIRE RAIL/SLEEPER ASSEMBLY--FASTENING SHOULD PREVENT THIS. DOWNWARD LOAD ON TOE OF RAIL CAUSED BY ELASTIC FASTENING IS CALLED TOE LOAD.

FASTENING (FORCES)

– VIBRATIONS- LOW FREQUENCY DUE TO PARASITIC MOTION and VERY HIGH FREQUENCY VIBRATIONS IN VERTICAL PLANE DUE TO RAIL WHEEL INTERACTION 700 TO 1200 CPS AND AMPLITUDE OF 0.1 MM TO 0.3 MM WITH ACCELRATION OF 70 TO 100 g

FASTENING (FORCES)

EFFECTS OF VERY HIGH FREQUENCY VIBRATIONS

– CAUSE OF FATIGUE FAILURE– LOOSENING OF FASTENING– LOOSENING OF BALLAST– LOSS OF TOE LOAD– EFFECT ON ROLLING STOCK– RAIL CORRUGATION

THE FASTENING SHOULD ABSORB AND DAMP THE HIGH ENERGY VIBRATIONS.

• RAIL IS CONNECTED WITH SLEEPER THROUGH AN ELASTIC MEDIUM, SUCH THAT IT ABSORBS ENERGY OF VIBRATIONS AND DOES NOT ALLOW TO CAUSE GAP BETWEEN RAIL AND SLEEPERS.

• THERE SHOULD BE DAMPED ELASTIC SUSPENSION WITHOUT PLAY. THE FASTENING PERMITS THE MOVEMENT OF RAIL WITHOUT CAUSING ANY GAP.

ELASTIC FASTENING

TYPE OF ELASTIC FASTENING

• TYPE I – IN WHICH TOE LOAD IS DERIVED FROM A FRICTIONAL GRIP OR NAILING EFFECT

• ERS, DS 18 AND MACBETH• TYPE II – IN WHICH LOAD APPLICATION IS

OBTAINED THROUGH A SCREW THREAD• HM, NABLA, VASSLOH

• TYPE III – IN WHICH THE LOAD IS PREDETERMINED AT THE DESIGN STAGE

• PENDROL

OBJECTIVES OF ELASTIC FASTENING

• ELASTIC RUBBER PAD• ABSORBS SHOCKS AND DAMP OUT VIBRATIONS• INCREASE FRICTIONAL RESISTANCE TO LONG. OR

LATERAL MOVEMENT OF RAIL.• DISTRIBUTE LOAD UNIFORMLY OVER SLEEPER• PROVIDE ELECTRIC INSULATION BETWEEN RAIL

AND SLEEPER• REDUCE NOISE LEVEL

MECHANISM

Source of Vibration

RailFastening

GRPSleeper

Ballast

Weight of rail

Vibration blocked by fastening spring

Vibration absorbed by rubber pad

Vibration absorbedBy stone friction &Spring action

Wt of sleeper

MECHANISM

FORMATION 15%

BALLAST 25%

ERC & GRP 60 %

ENERGY ABSORBED

LOAD

VOSSLOH FASTENING

Tension clamps

Guide plate

Rail Pad

Sleeper screw in dowel

COMPARISION BETWEEN ELASTIC FASTENING

TYPE II (BOLTED FASTENER) TYPE III ( CAST IN ANCHORAGE FASTENER)

THREADED ELEMENT APPLYING FORCE TO A SPRING STEEL ELEMENT

ANCHORAGE FIXED AT THE TIME OF CASTING

THREADED ELEMENT IS REMOVABLE

--------

RUBBER PAD BETWEEN RAIL AND SLEEPER

RUBBER PAD BETWEEN RAIL AND SLEEPER

TOE LOAD GENERATED BY TIGHTENING NUT

NO SUCH PROVISION

ADJUSTABLE TOE LOAD FIXED TOE LOADALLOWS REPLACEMENT OF ALL THE COMPONENTS IN THE EVENT OF DAMAGE

CASTING ANCHORAGES CANNOT BE RENEWED

OILING OF THREADS ONCE IN 3 YEARS

NO NEED.FIT AND FORGET TYPE

REQUIREMENT OF TOE LOAD

• ERC MARK III HAS AV. TOE LOAD OF 1000 KG UNDER 12 MM. DEFLECTION. – THE AV. STATIC TOE LOAD =1000x4 =4000 KG. ASSUMING 0.5 AS COEFF. OF FRICTION BETWEEN

RUBBER PAD AND RAIL, THE RAIL TO SLEEPER RESISTANCE IS APPROX. 2000 KG.

– THIS IS > AV. SLEEPER TO BALLAST RESISTANCE ( 1000 KG.). SO THE CHANCES OF RELATIVE RAIL TO SLEEPER MOVEMENT ARE LESS.

WHY GREASING?

FREE CONDITION

TOE LOAD850-1100Kg

FREE CONDITION

TOE LOAD850-1100Kg

MinimumCompressivestress

MinimumCompressivestress

MaximumCompressivestress

LOADEDCONDITION

AXLELOAD22 Tons

WHY GREASING?

PSC

INSERT

ERC

LINER

CORROSION

Torsional Force

ERC

Torsional Force

Figure shows the torsional force exerted due to corrosion.

WHY GREASING?

CORROSION

Jamming of ERC

Reduction of strengthLoss of Toe Load

End of function Life

End of function life

ERC greasing done regularly

ERC g

reas

ing

not d

one

Life cycle Time

Rate ofcorrosion

RUBBER PAD

• FUNCTIONS – DAMPING OF HIGH FREQUENCY VIBRATIONS– VIBRATIONALLY ISOLATE RAIL– PREVENT GAP

THE MECHANISM FOR ACHIEVING THIS IS – MOLECULES BROUGHT CLOSER UNDER FORCE, ENERGY DISSIPATION WHEN FORCE IS REMOVED.

DAMPING IS BEST WHEN RESTRAINING FORCE IS PREPORTIONAL TO AMPLITUDE OF VIBRATION.

RUBBER PAD

• COMMON TYPE OF PADS– PIMPLE TYPE PADS– GROOVED TYPE PADS

• THICKNESS 6 MM

LOAD DEFLECTION CHARACTERSTICS25

0 10 20 30 40 50 60

PR

ES

SU

RE

ON

RA

IL(T

)

DEFLECTION 1/100 MM

0

5

10

15

20SOLID PAD

GROOVED PAD

RUBBER PAD

• MATERIAL– NATURAL RUBBER– RIBBED SMOKED SHEET– BLEND OF STYRENE RUBBER/ POLY

BUTADIENE RUBBER

RUBBER PAD

• THE TOP SURFACE OF RUBBER PAD, WHICH COMES DIRECTLY IN CONTACT WITH RAIL, EXECUTE VERY HIGH FREQUENCY 1000 Hz (LOW AMPLITUDE 0.05- 0.1 mm) VIBRATIONS.

• WHILE THE BOTTOM SURFACE, WHICH COMES IN CONTACT WITH SLEEPER, EXECUTE LOW FREQUENCY 20 Hz VIBRATIONS.

RUBBER PAD

• FOR IMPROVING THE PERFORMANCE OF RUBBER PAD , MATERIAL SHOULD BE WITH VARYING ELASTIC PROPERTIES.

• SO THE TOP OF RUBBER PAD SHOULD HAVE HIGHER MODULUS OF ELASTICITY( HARDER) WHILE BOTTOM SHOULD BE OF SOFTER MATERIAL.

LINERS

– DISTRIBUTION OF TOE LOAD OVER LARGER AREA ON RAIL FOOT

– ALLOW FLEXIBILITY FOR USE OF DIFFERENT RAIL SECTION ON THE SAME/ COMMON SLEEPER

– PERMITS GAUGE ADJUSTMENT IN CURVED TRACK AND CORRECTION IN ALIGNMENT

– PROVIDE INSULATION BETWEEN RAIL AND INSERT

LINERS

• THE REQUIREMENTS OF LINER– THE LINER SHOULD HAVE PROPER SLOPE TO

MATCH WITH RAIL FOOT SLOPE– THE VERTICAL LEG OF LINER SHOULD FIT

PROPERLY BETWEEN RAIL AND MCI INSERT TO MAINTAIN GAUGE

– IT SHOULD BE EASY TO FIX & MANUFACTURE

INSERTS

• IT IS EMBEDDED IN CONCRETE AT THE TIME OF CASTING

• THIS IS ANCHORAGE FOR ERC• GRIPS THE CLIP EFFECTIVELY• PROVIDES LATERAL SUPPORT TO RAIL• SHOULD HAVE ADEQUATE PULL STRENGTH

(MORE THAN 10T)

INSERTS

• TOE LOAD IS FUNCTION OF DIA. OF HOLE AND DIFFERENCE BETWEEN APEX OF HOLE AND TOP OF SHOULDER

• CORRECT POSITIONING IS IMPORTANT – VERTICAL POSITIONING FOR TOE LOAD– LATERAL POSITIONING FOR GAUGE

• THE GAP BETWEEN TOE AND RAIL SEAT SURFACE SHOULD BE 8 MM.

MAINTENANCE OF RAIL JOINTS ON CONCRETE SLEEPERS

• RAIL JOINTS TO HAVE 1 M. LONG FISHPLATE• RUBBER PAD OF THE JOINT & SHOULDER

SLEEPERS TO BE RENEWED EVERY YEAR• CRIB & SHOULDER BALLAST AROUND THE JOINT

TO BE SCREENED EVERY YEAR• THE FISH PLATE SHOULD BE GROUND TO

ACCOMMODATE ELASTIC RAIL CLIP / PROVIDE J- CLIP

Thank You