Presentation on railway construction and maintenance

Presentation by Mohd Bakhsh

Consultant/Civil/Rail Vikas Nigam Ltd/Kota

Fr Dy.Chief Engineer/WR As A GUEST LECTURER at Rao Prahlad singh College of Engineering at Balana Mohindergarh Haryana on 24TH November,2014

Track Formation Diagram

Railway Gauges in India

Broad Gauge - 5'6" (1676mm)

Meter Gauge - 1m

Narrow Gauge - 2'6" (762mm)

The slab tra ck

Axle: P = 200 kNWheel : Q = 100 kN Mean stress

Dimensional Diagrams

RAILWAY CONSTRUCTION AND MAINTENANCE

Track geometries:- gradients, types of gradients, curves, types of curves, super elevations, relation super elevation with gauge ,speed and radius of curves, pointing crossing, technical terms, turn out switches, type of switches, crossings, type of crossing, junction, type of junction, plating, method of platting, relaying of track, method of relaying of track, railway station, purpose, site selection, requirements, classification of stations, yards, classification of yards, necessity of equipment, level crossing, signals, classification of signals,interlocking,method of inter locking, maintenance and drainage, classification of maintenance.

TRACK GEOMETRY horizontal and vertical. Track geometry is three-

dimensional geometry of track layouts and associated measurements used in design, construction and maintenance of railroad tracks. The subject is used in the context of standards, speed limits and other regulations in the areas of track gauge, alignment, elevation curvature and track surface. Although, the geometry of the tracks is three-dimensional by nature, the standards are usually expressed in two separate layouts for

TRACK GEOMETRY Alignment In fixing the alignment of railway line, the following points

require attention. Position of Curves Degree of Curvature. Transition Curves Gradients Vertical Curves Alternative Alignments Rivers Important Rivers High Flood Levels Diversion of Rivers

TRACK GEOMETRY Protection Works Construction of New Railway Bridges Over Head Electric Traction Provision of traction over-head equipment

structures on new bridges Station Sites The site for stations should be completely

surveyedand sharp curves should be avoided in the vicinity of the station.As far as possible steep falling curve should begin after 45 m of the station limit.

Junction Arrangements It is advisable to join nearly 2 Km away from the

centre of the junction and hence run parallel to the existing line.

EQUIPMENTS FOR SURVEYING GEOMETRY The main surveying instruments in use around the world are

the theodolite and steel band, the total station, the level and rod and surveying GPS systems. Most instruments are placed on a tripod when in use. Tape measures are often used for measurement of smaller distances. 3D scanners and various forms of aerial imagery are also used.

The grade (also called slope, incline, gradient, pitch or rise) of a physical feature, landform or constructed line refers to the tangent of the angle of that surface to the horizontal. It is a special case of the gradient in calculus where zero indicates gravitational level. A larger number indicates higher or steeper degree of "tilt". Often slope is calculated as a ratio of "rise" to "run", or as a fraction ("rise over run") in which run is the horizontal distance and rise is the vertical distance.

RAILWAY TRACK GRADIENTS

1) Ruling gradient

2) Momentum Gradient

3) Pusher gradient

4) Gradient at stations

1) RULING GRADIENT

2) MOMENTUM GRADIENT

3) PUSHER GRADIENT

4) GRADIENT AT STATIONS


d = distance traveled horizontallyΔh = risel = slope lengthα = angle of inclination

RAILWAY TRACK GRADIENT

Curve with superelevation

Superelevation between the inside and outside rails

RAILWAY TRACK GRADIENTS 1) Ruling gradient: The steepest gradient allowed

on the track section. It determines the max load that the locomotive can haul that section. The steep gradient needs more powerful locomotives, smaller train loads, lower speed, resulting in costly hauling.

–In plains: 1 in 150 to 1 in 200 –In hilly regions: 1 in 100 to 1 in 150 2) Momentum Gradient: The gradient on a section

which are steeper than the ruling gradient acquire sufficient momentum to negotiate them are known as momentum gradient.

RAILWAY TRACK GRADIENTS 3) Pusher gradient: As stated above a ruling gradient

limits the maximum weight of a train which can be hauled over the section by a locomotive. If the ruling gradient is so severe on a section that it needs the help of extra engine to pull the same load than this gradient is known as pusher of helper gradient. In Darjeeling Railways 1 in 37 pusher gradient is used on Western Ghat BG Track.

4) Gradient at stations: at stations gradient are provided sufficient low due to following reason:

–To prevent movement of standing vehicle –To prevent additional resistance due to grade. On Indian railways, maximum gradient permitted is 1 in

400 in station yards.


Grade compensation on curves If a curve is provided on a track with ruling

gradient, the resistance of the track will be increased this curve. In order to avoid resistance beyond the allowable limits, the gradients are reduced on curves. The reduction in gradient is known as grade compensation for curves.

•BG track: 0.04% per degree of curve •MG track: 0.03 % per degree of curve •NG track: 0.02 % per degree of curve

DEGREE OF CURVES

A curve is defined by its degree or radius. The degree of a curve is the angle subtended at the center by a chord of 100 feet or 30.48m.

If R is the radius of curve, •Circumference of the curve= 2 ∏ R •Angle subtended at the center by the circle = 360

degree •Angle subtended by the arc of 30.48m = 1750/R Thus, a 1 degree curve has a radius of 1750 m

SUPER ELEVATION OF CURVE

Superelevation on Curves (Cant) Cant is defined as the difference in height between the inner

and outer rails on the curve. It is provided by gradually raising the outer rail above the inner rail level. The inner rail is considered as the reference rail and normally is maintained at its original level. The inner rail is known as the gradient rail.

Function of superelevation: – Neutralizes the effect of lateral force. – It provides better load distribution on the two rails. – It reduces wear and tear of rails and rolling stock. – It provides smooth running of trains and comforts to the

passengers.

SPEED ON CURVES Equilibrium speed: It is the speed at which the effect of centrifugal

force is exactly balanced by the superelevation provided. It can also be said that when the speed of a vehicle running on a curved track is such that the resultant weight of the vehicle and the effect of radical acceleration is perpendicular to the plane of rails and the vehicle is not subjected to an unbalanced radical acceleration, is in equilibrium then its particular speed is called equilibrium speed.Maximum permissible speed: This is the highest speed which may

be allowed or permitted on a curved track taking into consideration of the

radius of curvature, actual cant, cant deficiency, cant excess and the length

of the transition curve. When, the maximum permissible speed on the curve

is less than the maximum sanctioned speed of the section of a line,

permanent speed restriction become necessary on such curves.

CANT DEFICIENCY

Cant deficiency is the difference between the equilibrium cant (theoritical) necessary for the maximum permissible speed on a curve and the actual cant provided there. As per Indian Railways, Cant deficiency is recommended as follow:

BG Track: 75 mm MG track: 50 mm NG track: 40 mm

CANT EXCESS When a train travels on a curved rack at a speed

lower than the equilibrium speed, then the cant excess occurs. It is the difference between the actual cant provided and the theoretical cant required for such lower speeds. Maximum value for cant excess is

BG track: 75 mm MG Track: 65 mm

CENTRIFUGAL FORCE When a body moves on a circular curve, it has a

tendency to move in a straight direction tangential to the curve. This tendency of the body is due to the fact that the body is subjected to a constant radial acceleration.

POINTS AND CROSSINGS

LAY OUT OF POINTS AND CROSSINGS

METHODS OF CONSTRUCTION

1.Telescopic Method of Construction2.Trame line Method of Construction3.Mechanaical Methods

1.TELESCOPIC METHOD OF CONSTRUCTION

In this method of construction rails, sleepers, fastenings are unloaded from the material train as closer to raill head as possible. The sleepers are carried by cart or by men along the adjoining service road and spread on the ballast. The rails are then carried on pairs to the end of last pair of connected rails and linked

2.TRAME LINE METHOD OF CONSTRUCTION

This method is used where tram carrier are

installed for carrying earthwork or in rainy season due to difficulty in

movement of cart. The basic difference between Telescopic and Trame line lies in the conveyance

and spreading of sleepers.

3.MECHANAICAL METHODS This method is extensively used in

Britain and America by using special track

laying machine. There are two types of machines available

1.In the first type track material carried by the material train and delivered at rail head and laid in the required position by means of projecting arm mounted on the truck nearest to the rail head. The material train moves forward on the assembled track and operation repeated.

MECHANICAL METHOD In the second method a long cantilevered

arm projecting beyond fitted on the wagon. A panel of assembled track consisting pair of rails with number of sleepers on the ballast layer. This panel is carried by special trolley running over the wagons of material train to the jibs. It is lowered by the jib at the required position and connected to the previous panel. The train moves on and operation repeated.

MAINTENANCE OF RAILWAY TRACK -Existing System of track Maintenance 1.Manually 2. Three tier system of maintenance The track should be maintained either by conventional system of

track maintenance or by three – tier system of track maintenance. In both the systems, track requires to be overhauled periodically

with the object of restoring it to best possible condition, consistent with its

maintainability. Periodicity of overhauling depends on several factors, such as type of track

structure, its age, volume of traffic, rate of track deterioration, maximum permissible speed,

system of traction, condition

TRACK MAINTENANCE (A) Conventional system of track

maintenance- in this track is maintained manually

(B) Three tier system of track maintenance: - (1) 3- tier system of track maintenance shall

be adopted on sections nominated for mechanized maintenance. This shall consist

of the following 3 tiers of maintenance- (i) On track machines (ii) Mobile maintenance units (iii) Sectional gangs

TRACK MAINTENANCE (2) Large track machines for track maintenance include tie-

tamping machines for plain track and points and crossings, shoulder ballast cleaning

machines, ballast-cleaning machines, ballast regulating machines and dynamic track stabilizers. These machines shall be used as per the various instructions

issued in Indian Railways Track Machines Manual. These machines shall be deployed to carry out the following

jobs. (a) Systematic tamping of plain track as well as points and

crossings (b) Intermediate tamping of plain track as well as points and

crossings (c) Shoulder ballast cleaning (d) Ballast profiling / redistribution

TRACK MAINTENANCE (e) Track stabilization (f) Periodical deep screening (3) Mobile Maintenance Units- (a) The mobile maintenance units (MMU)

shall consist of two groups- (i) MMU-I one for each PWI’s section (ii) MMU-II one for each sub division (b) The functions of MMU shall be as below:

TRACK MAINTENANCE3. Track Relaying Activities and Existing system of

Relaying

Track relaying activities involves following activities:

1.Plain track relaying viz.CTR, TRR and TSR2.Turnout relaying At present both these activities are

performed both manually and by machines.

LIMITING VALUES FOR DESIGN AND CONSTRUCTION OF RAILWAY

Superelevation, Cant deficiency and Cant excess

Where C is cant/super elevation in mm. G is the gauge of track+ width of rail head in mm. R is the radius of the curve in meters

STA TIO N C LA SSE S

The different classes of stations? IR's classification of stations is linked to their rules for block system

working. Class A: Such a station is one where the Line Clear indication for the

block may not be given unless the line where the train is to be received is clear at least for up to the starter signal (or, in some cases, for at least 400m ahead of the home signal). These are stations where many trains normally run through without stopping at a high speed, hence the need for the safety margin to prevent accidents in cases of trains overrunning signals. [4/00]

Class B: Such a station is one where the Line Clear indication may be given before the section of the line within the station has been cleared for reception of a train. Branch lines and routes with lower running speeds fall into this category.

STATION CLASSES

Class C: This is a station (or block hut) marking an end of a block section, with light traffic or where no trains are booked to stop, such as an intermediate block post. (Sometimes these stations exist only in the form of a signal cabin that controls the approach to another station.) Permission to approach may not be given for a train unless the whole of the last preceding train has passed complete at least 400m beyond the home signal and is known to be continuing on its journey.

Class D: This is a station which does not form the boundary of a block section but which does form a stopping place for trains. Trains are stopped by various ad hoc arrangements prescribed in view of the local conditions -- the driver may simply know to stop the train there, or it may be flagged down on demand, etc. Also known as anon-block station or flag station.

STATION CLASSES

Stations of classes A through C are known as block stations. The Class C stations are also sometimes known asblock huts or block posts. Class D stations are known as non-block stations - they do not mark the ends of block sections. (Note that there also exist Intermediate Block Posts where block sections can be terminated without the presence of a station.)

Any station that is not classified under one of the classes A through D is known as a Special Station and must use specific working rules issued by the Commissioner of Rail Safety.

Sometimes stations are classified as Class A if there is a bridge or steep gradient just before the station in one or both directions, so that it is not safe for trains to stop there before entering station limits.

STATION CLASSES

COMMERCIAL CLASSIFICATION Commercial Classification: Passgr.Earnings Category A stations Rs 60 m/annum Category B stations Rs 30-60 m/annum Category C stations Fluctuating earning Category D stations Rs 10-30 m/annum Category E stations Lower earnings Category E stations Halt Stations

STATION CLASSES

Category A stations High level Platform Category B stations Low level Platform Category C stations High level Platform Category D stations Low level Platform Category E,F stations Rail level Platform

GENERAL INFORMATION ON SIGNALLING AND TRAIN WORKING

Different kinds of signalling and train working systems are in use in India.

1.The absolute block system is the most widespread method of train working on IR. The block sections may be handled manually or automatically, or by some combination of those. Some sections still use different forms of physical token systems such as the Neale's Ball Token instruments.

http://www.irfca.org/faq/faq-signal4_b.html


2.Semaphore Signalling: Very old system(lower quadrant and upper quadrant) formerly with oil lamps now with light lamps.

Color light signal system(automatic or manual with 2-3-4-aspect)

3 AWS (Automatic Warning System) Itis an in-cab signal warning system, is used in

suburban EMU systems, primarily in Mmbai sub-urban

4. centralized traffic control (CTC)


A few areas have seen the introduction of forms of centralized traffic control (CTC) in conjunction with automatic colour-light signalling. (CTC was first introduced on the NER's busy MG section between Gorakhpur and Chupra, and later on the Bongaigaon-Changsari section of NFR.) The suburban section of Madras Egmore - Tambaram also has CTC.

STANDARDS OF INTERLOCKING THAT IR SPECIFIES FOR STATIONS A Standard I A Standard II A Standard III A Standard I:interlocked station has mechanical

interlocking. It also usually has just one running line and a loop line (and perhaps a couple of sidings). These are usually branch line stations. The points are worked by point levers situated near the points, and the signals are worked from interlocking frames in the signal cabin. Key locking (see above) is used, but the mechanism is such that a key obtained from the points mechanism after setting the points for one route must be used on the signal post locking mechanism to pull off the corresponding signal(s) and also to operate the block instrument, thus interlocking the signals and points.

STANDARDS OF INTERLOCKING THAT IR SPECIFIES FOR STATIONS

All signals must be operated from the same interlocked frame on the platform, under the station master's control. Through running speed for trains is restricted to 50km/h. (? Some sources say 45km/h.) An Outer signal must be provided, as must a bracketed Home signal to give drivers indication of whether the train is being received on the main line or a loop line so they can regulate its speed appropriately. Starter signals are optional. The main line does not have to be completely isolated from the adjacent loop lines.


A Standard II: Interlocked station may be mechanically or electrically interlocked (usually the latter). These are usually non-trunk main line stations. The main running line at such a station can be completely isolated from the loops and shunting sidings on both sides. In mechanical interlocking, plunger locks or other similar mechanisms must be used to keep the points locked in position when set for a route. Plunger locks may be operated from the cabin, or line-side. In electrically interlocked systems, setting the points activates electrical circuitry that enables or disables the appropriate signal levers and block instruments.


A Warner or Distant signal must be provided, along with an Outer and a bracketed Home. Starters are optional, although if there is no starter the Warner must be locked with the block instrument. The signals may be operated from the platform under the station master's control or from a cabin. Through running speed for trains is restricted to 75km/h.

Standard I and II stations sometimes do not have starter signals, only home signals for receiving trains; in such a case trains are dispatched using flag or lamp signals from the station. Standard I and II stations usually have only one signal cabin.


A Standard III interlocked station has points and signals that are either interconnected mechanically within the same mechanism, or electrically as with route-relay and panel interlocking. These are usually stations on trunk routes. Usually two signal cabins whose signal and points controls are interconnected are provided. These stations usually have the full complement of signals including warners or distants, outer and bracketed home signals, and also starter signals, for receiving and dispatching trains. (Advanced starters are still optional.) All points must be operated centrally, or in coordination between the two (or more) interconnected cabins. Through running speed for such stations is limited only by the speed limit for the section. The loop lines at such stations have to be completely isolated from the main running line by means such as sand humps, over-run lines, trap points, or derailing switches etc.


In some cases, especially with signals and points too far from the station building for direct mechanical operation, the operation of remote points and signals is dependent on keys provided by the Station Master; without the key the point or signal lever cannot be operated. Interlocking is ensured by having the key dispensed from a key instrument that is connected to the block instrument under the Station Master's control. Common key dispensing mechanisms were the Hepper's Key Instrument, the Electric Slide instrument, and the Interlocked Key Box. In other cases, the block instruments may be located in the cabins, but the signals controlled directly by the Station Master

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T H A N K S

Presentation on railway construction and maintenance

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Transcript of Presentation on railway construction and maintenance