ATRAINING REPORTONINDIAN RAILWAY(DRM Office- Agra U. P.)BYShivam raj singhSubmitted to the department of Civil EngineeringIn partial fulfilment of the requirementsFor the degree ofDiplomaInCivil Engineering

Eshan College of Engineering, farah, MathuraUtter Pradesh Technical University2014-15

DECLARATION

I hereby declare that this submission is my own work and that, to the best of my knowledge and belief, it contains no material previously published of written by another person which to a substantial extent has the award of any other degree or diploma of the university of other institute of higher learning except where due acknowledgement has been made in the text.

Shivam raj singhFinal: Diploma (Civil Engineering)Date :

ACKNOWLEDGEMENT

Its a great pleasure to present this project report on title of report in partial fulfilment of Diploma program under Eshan College of Enginnering, farah Mathura affiliated to Board of Technical Education, Lucknow. At the outset, We would like to express my immense gratitude to our project guide.

I are falling short of words for expressing my feelings of gratitude towords him for extending their valuable guidance about market and support for literature, critical reviews of our project report and above all the moral support he had provided me with all stages of this project.

I would also like to thank my friends and my entire group member for their help and cooperation throughout the project.

Shivam raj singh Final Diploma (Civil Engineering)Date:

ABSTRACTThis project report contains the detail description about the RAILWAY it describes its objectives, coverage, implementation, committee and maintainance. It also shows its case study analysis made for this project.

LIST OF CONTENT I. DECLARATIONII. ACKNOWLEDGEMENTIII. ABSTRACT

CHAPTER 11.1 INTRODUCTION1.2 RAILWAY BOARD1.3 ADVANTAGES OF RAILWAY1.4 CLASSIFICATION ON INDIAN RAILWAY1.5 RAILWAY TRACKCHAPTER 22.1 RAILWAY TRACK2.2 REQUIREMENT OF AN IDEAL PERMANET WAY2.3 CAPACITY OF A RAILWAY TRACK2.4 GAUGES IN RAILWAY TRACK2.5 RAILWAY TRACK CROSS-SECTION2.6 CONNING OF WHEELCHAPTER 33.1 RAIL3.2 COMPOSITION OF RAIL STEEL3.3 REQUIREMENT OF RAILS3.4 TYPES OF RAIL SECTION3.5 SECTION OF RAILS3.6 LENGTH OF RAILS3.7 WEAR ON RAILSCHAPTER 44.1 SLEEPERS4.2 REQUIREMENT OF SLEEPERS4.3 CLASSIFICATION OF SLEEPERS4.4 TIMBER OR WOODEN SLEEPERS4.5 METAL SLEEPERS4.6 CONCRETE SLEEPERS

CHAPTER 55.1 DIFINITIONS5.2 FUNCTIONS OF THE SUBGRADE OR FORMATION5.3 SUBGRADE METERIAL AND ITS IMPROVEMENT

CHAPTER 66.1 TRACK ALIGNMENT6.2 BASIC REQUIREMENTS OF GOOD ALIGNMENT6.3 FACTORS IN SECTION OF GOOD-ALIGNMENT

CHAPTER 77.1 NECESSITY OF GEOMETRIC DESIGN OF A RAILWAY TRACK7.2 SUPERELEVATION OR CANT7.3 CURVES

CHAPTER 11.1 INTTRODUCTION

Transportation is regarded as an index of economic, social and commercial progress of a country. The transport industry , which undertakes nothing more than mere movement of presons and things from one place to another, has constituted. The most important activities of men in every stage of advanced civilisation. The whole structure of industry and commerce rests on the well laid foundation of transport. No region or country can ever flourish if is it lacks adequate transport facilities . An adequate transportation is indispensable for economic and social progress of a nation and the world as a whole.

Land, water and Air have been used by the mankind for developing the transport modes like railways, highways , waterways , Airways , etc.

1.2 RAILWAY BOARD

The responsibility of the administration and management of the Indian Railways rests with the Railways. The Railways Board exercises all the powers all the powers of the Central Government in respect of regulation, construction, maintenance and operation of the Railways. The Railway Board consists of the Chairman, Financial Commissioner for Railways and five other financial members.

The Financial Commissioner for Railways is vested with full power of the Government of India to sanction Railway expenditure and ex-offico secretary to the Government of India in the Ministry of Railway in financial matters.

The Members of the Railway Board are separately incharge of matters relation to Stadd, Civil engg, Traffic, Mechanical Engineering and Electrical Engineering. Railway Board is assisted by a number of technical offers designated as Adviser

1.3 ADVANTAGES OF RAILWAYS

Railway have brought about many political, social and economic changes in the life of indian people:

a) Political Advantages:

I. Railways have united the people of different castes, religions customs and traditions.II. With the adequate network of railways, the central administration has become more easy and effective.III. Railway have contributed towards development of a national mentality in the minds of people.IV. The role of railways during emergencies in mobilising troops and war equipment has been very significant.V. Railways have helped in the mass migration of the population.

b) Social Advantages:

I. The feeling of isolation has been removed from the inhabitants of the indian villages.II. By travelling together into the compartment without any restriction of caste. The feeling of caste difference has disappeared considerably.III. The social outlook of the masses has been broadened through railway journeys.IV. Railway has made it easier to reach places of religious importance.V. Railways provide a convenient and safe mode of transport for the country.

c) Techno-Economic Advantages:

I. Cost saving in transportation of long haul bulk traffic.II. Energy-Effciency (railways consume one-seveth of fuel uses by the road sector).III. Environment friendliness.IV. Higher safety (fatal accidents one-tenth of road sector in india)V. Efficient Land use and ease in capacity expansion.

1.4 CLASSIFICATION ON INDIAN RAILWAYS

Railway board has classified the Indian Railway lines on the basis of the importance of route, traffic carried and maximum permissible speed on the routes, into the following 3Main categpries:

1) Truck Routes.2) Main Lines.3) Branch Lines.

Railway board has given the following specification for these lines.

1) Truck Routs. The following 6 routes of B.G. and 3 routes of M.G. have been classified as truck routes:

On B.G. 1.Delhi-Mughalsarai-Howarh. 2.Delhi-Kota-Mumbai. 3.Howrah-vihyawada-chennai

On M.G 1.Lucknow-Gorakhpur-Guwahati. 2.Delhi-Jaipur-Ahmedabad

The following track standard for trunk routes have been specified:

ITEMSB.G.M.G.

1. Maxim. Permissible speed 2. Rail section3. Sleeper density4. Ballast cushion120 km p.h

54kg/m or heavler(n+7)25cm below sleeper

80km p.h

37.2 kg/m (i.e.75R)(n+7)25cm below sleeper

2) Main Lines. All lines other than trunk routes carrying 10gross million Tonnes (G.M.T) per annum or more for B.G and 2.5 G.M.T or more for M.G or where maximum permissible speed allowed is 100km. p.h for B.G and 75km p.h for M.G are classified as main lines.the following specification have been laid down for main lines by Railway Board.

ITEMSB.GM.G

1. GMT/Annum2. Maxm. Permissible speed 3. Track relaying period4. Rail section

>10100km p.h.

20 years52km/m>2.575km p.h.

30 years37.2 kg/m

3) Branch Lines These are classified on the basis of following criteria:All those B.G. lines which carry less than 10 Gross Million Tonnes (G.M.T) per annum and have maximum permissible speed of less than 100km p.h are classified as branch lines for M.G. track, all those lines which carry less than 2.5 G.M.T per annum and have maximum permissible speeds less than 75km p.h are classified as branch lines.

i. B.G. iocomotive (WG/WP type) and Bobs wagons would be allowed to operate over all branch lines at a reasonable speed.ii. M.G. Engines (YG/YP type) and wagons with a maximum axle load of 12 tones would be permitted to oprate on all branch lines at a reasonable speed.

CHAPTER 2

2.1 Railway Track

2.1 THE PERMANENT WAY:

The combination of rails, fitted on sleepers and resting on ballast and subgrade is called the railway track or permanent way. Sometimes temporary tracks are also laid for conver=yance of earth and materials during construction works. The name permanent way is given to distinguish the final layout of track from these temporary tracks. Fig. throws a typical cross section of a permanent way on an embankment.

In a permanent way, the rails are joined in series by fish plates and bolts and then they are fixed to sleepers by different types of fastenings. The sleepers properly spaced, resting on ballast. The layer of ballast rests on the prepared subgrade called the formation.

The rails act as girders to transmit the wheel load to the sleepers in position with respect to the proper tilt, gauge and lavel, and transit the load from rails to the ballast.

The ballast distributes the load over the formation and holds the sleepers in position.

2.2 REQUIREMENTS OF AN IDEAL PERMANET WAY:

Permanent track is regarded to be semi-elastic in nature. There is possibility of track getting disturbed by the moving wheel loads. The track should, therefore, be constructed and maintained keeping the requirements of a permanent way, in view, so as to achieve higher speed and better qualities with less future maintenance. Following are some of the basic requirements of a permanent way:

i. The gauge should be correct and uniform.ii. The rails should be in proper level. In a straights track, two rails must be at the same level. On curves, the outer rail should have proper superelevation and there should be proper transition at the junction of a straight and a curve.iii. The alignment should be correct, i.e, it should be free from kinks or irregularities.iv. The track should be resilient and elastic in order to absorb shocks and vibration of running track.v. The radii and superelevation on curves should be properly designed and maintained.vi. Drainage system must be perfact for enhancing safety and durability of track.vii. If there is trouble from the creep, the preventionary measures should be to prevent it.

2.3 CAPACITY OF A RAILWAY TRACK:

Capacity of a railway track(or track capacity) is the hourly capacity of the track to handle the trains safely or in other words it is the number of trains that can be run safely on a track per hour. The track capacity can be increased by the following ways:

i. By achieving faster movement of trains on a track,andii. By decreasing the distance between successive trains.

The following are some of the general measures which can be taken to increase the track-capacity.

1. All the trains should be made to run at the same speed for which uniformity of gauge and traction should first be achieved in the country.2. All sections should be made of equal length.3. The speed of trains can be increased by adopting desel or electric traction.4. A reduction in the time of stoppages of trains.5. A length of section should be decreased by providing additional crossing section.6. The length of crossing sections should be increased in order to enable the longer goods trains to pass.7. New lines should be constructed for operational and industrial purposes.8. The section with increased traffic and all important yards speeds on main trunk routes.9. The traffic control on B.G. and M.G. should be centralized.

2.4 GAUGES IN RAILWAY TRACK:

Definition: The gauge of a railway track is defined as the clear distance between inner or running faces of two track rails. The distance between the inner face of a pair of wheels is called the wheel gauge

Different Gauges In India and Abroad:In 18th century, the British railways were using the flanges on the outsides of rails and the gauges was defined as the distance between the outer faces .

Type of gaugegauge widthStandard gauge (B.G) = 1.67m.Metre gauge (M.G) = 1.0m.Narrow gauge (N.G) = 0.762m.Feeder track gauge (L.G) = 0.610

Selection of Gauge:

The following factors govern the choice among the different gauge.

Cost of Construction. There is little increase in the initial cost if we select a wider gauge, this is due to following reasons:

The cost of bridges, tunnels station buildings, staff quarters, signals, cabins and level crossings is the same for all the gauges.The cost of earth work ballast, sleepers, rails, etc. would proportionally increase with increase in gauge width.There is little proportional increase in the acquisition of land for permanent track with increase in gauge.The cost rolling stock is independent of the gauge used for the same volume of traffic.

Volume and Nature of Traffic. It is evident that with greater traffic volume and greater load carrying capacity, the trains should be run by a better traction technique or by better locomotives. For heavier loads and high speed. The wider gauges are required because subsequently the operating cost per tonne-km is less for higher carrying capacity.

Development of the Areas. Narrow gauges can be used to develop the thinly populated areas by joining the under developed areas with developed or urbanised areas.

Physical Features of the Country. Use of Narrow gauge is warranted in hilly regions where board and meter gauges are not possible due to sleep gradients and sharp curves. In plans also, where high speed is not required and the traffic is light. N.G. is a right choice.

Speed of Movement. The speed of a train is almost proportional to the gauge. Speed is the function of diameter of wheel, which in turn is limited by the gauge. The wheel diameter is generally 0.75 times that of the gauge. Lower speeds discourage the customers, and so for maintaining high speeds, the board gauge is perfered.

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 experienced in an non-uniform system. The Uniformity of gauges results in the following advantages:

1. The delay, cost and hardship in transhipping passengers and goods from the vehicals of one gauge to another is avoided.2. As the transhipping is not required, there is no breakage of goods.3. Difficulties in loading and unloading are avoided and labour expenses are saved.4. Possibility of thefts and misplacement, while changing from one vehicle to another, is eliminated.5. Large sheds to store goods are not required.6. Labour strikes, etc. do not affect the service and operation of trains.7. Locomotives can be effectively used on all the tracks if a uniforms type of gauge is adopted.

2.5 RAILWAYS TRACK CROSS-SECTIONS:

The typical cross-section of a single line and double line, in cutting and embankment, on straight and curved tracks for steam traction and electric traction, have been show in fig.

2.6 CONNING OF WHEELS:

The distance between the inside edges of wheel flanges is generally kept less than the gauge of the track. So there is a gap between the wheel flanges and running edges of the rails, nearly equal to 1cm. (3/8) on either side. Normally, the tread of wheels is absolutely dead centre of the head of the rail, as the wheel is coned to keep it in this central position automatically. These wheels are coned at a slope of 1 in 20 .

The advantages of coning the wheels are:i. To reduce the wear and tear of the wheel flanges and rails, which is due to rubbing action of flanges of lateral with inside faces of the rail head.ii. The prevent the wheels from slipping to some exient.

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 the further movement and axle retreats back to its original position.

On a curved path, it is seen that due to rigidity of the wheel base either of the wheel must slip by an amount equal to the difference of length or the axle must slightly move outwards to provide a tread of longer diameter over the inner rail .

If the tread diameter on both the rails is same, the amount of slip will be given by

Slip=0 (R2-R1)

Where,Outer radius, R2 = R+ C/2

Inner Radius, R1 = R G/2

G= Gauge Therefor the slip is about 0.029m per degree of central angle.

Coning of wheel on curves is not of much use as the leading axle if due 10 centrifugal force moves towards the outer rail the rear axle will move towards the inner rail full advantage of cuning wheels cannot be availed. In other words, there is no free lateral movement of wheels and this leads to following disadvantages:

I. Pressure on outer rail is more while on inner rail it is less. This results is wear of outer rail.II. Due to the centrifugal force, the horizontal components tends to turn the rail out and gauge has widening tendency.

CHAPTER 3

3.1 RAILS

The rails on the track can be considered as steel girders for the purpose of carrying axle loads. They are made of high carbon steel to withstand wear and tear. Flat footed rails are mostly used in railway track.

FUNCTION OF RAILS:

Rails in the railway track serve the following purposes:

i. Rails provide a hard, smooth and unchanging surface for passage of heavy moving loads with a minimum friction between the steel rails and steel wheels.

ii. Rails bear the stresses developed due to heavy vertical loads, lateral and braking forces and thermal stresses.

iii. The rail material used is such that it gives minimum wear to avoid replacement charges and failures of rails due to wear.

iv. Rails transmit the loads to sleepers and consequently reduce pressure on ballast and formation below.

3.2 COMPOSITION OF RAIL STEEL:

To meet the above functions, rails should be good steel meeting all its requirements. Generally rails are made by open hearth process:

a. For Ordinary Rail. High carbon steel with following composition is used:

Carbon(c) - 0.55 to 0.68 per centManganese(Mn) - 0.65 to 0.90 per centSilicon(Si) - 0.05 to 0.3 per centSulphur(S) - 0.05 per cent or belowPhosphorus(P) - 0.06 per cent or below

b. For rails on Points and Crossings. Medium carbon steel with following composition is used:

Carbon(C) - 0.5 to 0.6 per centSilicon(Si) - 0.05 to 0.20 per cent

3.3 REQUIREMENTS OF RAILS:

Rails act is continuous girders carrying axle loads. They should meet the following requirements to serve intended purposes:

i. They should be of proper composition of steel as given above and should be manufactured by open hearth or duplex process.ii. The vertical stiffness should be high enough to transmit the load to several sleepers underneath. The height of rail should, therefore, be adequate.iii. Rails should be capable of withstanding lateral forces. Large width of head and foot endows the rails with high lateral stiffness.iv. The head must be sufficiently deep to allow for an adequate margin of vertical wear. The wearing surface should be hard.v. Web of rails should be sufficiently thick to bear the load coming on it and should provide adequate flexural rigidity in horizontal plane.vi. Foot should be wide enough so that rails are stable against overturning, especially on curves.vii. Bottom of the head and top of the foot of rails should be so shaped as to enable the fish plates to transmit the vertical load efficiently from the head to the foot at rail joints.viii. Relative distribution of material of rail in head, web and foot must balanced, for smooth transmission of loads.ix. The fillet radii must be large to reduce the concentration of stresses.

3.4 TYPES OF RAIL SECTIONS:

The three types of rail sections which have been tried so far the construction of railway track me:

1. Double headed rail (D.H. Rails)2. Bull headed rails (B.H. Rails)3. Flat footed rails (F.F. Rails)

In the beginning, the rails used were double headed (D.H.) of a dumb-bell section. The idea behind using of these rails was that when the head has worn out in course of time, the rail can be inverted and reused. But experience showed that such indentations are formed in lower table due to which smooth running over that surface at the top was impossible. The next evolution was that of a bull headed(B.H.) rails. In which the head was made a little thicker and stronger than the lower part, by adding more metal to it, so that even after wear, it can withstand stresses.

Side by side with the B.H. rails, flat-footed rails also called Vignoles rails after the name of the inventor, were developed. It was originally thought that the flat-footed rails could be fixed to sleepers directly and would eliminate the need for chairs and keys required for the B.H. rails. However, it was observed that heavy train loads caused the foot of the rail to sink into wooden sleeper, making the spikes work loose.

3.5 SELECTION OF RAILS:

A rail is designated by its weight per unit length. The various important factors to be considered in deciding the weight of rail to be used are as follows:

1. Speed of the train.2. The gauge of the track.3. The axle load and name of traffic.4. Type of rails, i.e. whether D.H or B.H or F.F. rails.5. Spacing of sleepers6. Maximum permissible wear on top rails.

It is evident that heavier the rail, bigger would be the section and higher would be its load carrying capacity.

A general rule adopted is to specify a certain constant value of the ratio between the weight of the rail and the locomotive axle load. In India this ratio is 510.

Weight of the rail in tonnes/locomotive axle load in tonnes = 1/510

Thus , for a locomotive of axle load of 22.86 tonnes, the weight of rail required will be

22.86*1000/510 = 44.8 kg.

This 44.8 kg section includes 5 p.c. wear. The necessity of today is to increase the weight of the rail, i.e to decrease the ratio i.e 1/510 because heavier rails are preferred to light rails

3.6 LENGTH OF RAILS:

The rails of larger length are preferred to smaller length of rails, because they give more strength and economy for a railway track. The weakest point of a track is the joint between two rails. Lesser the number of joints, lesser would be the number of fish plates and this would lead to lesser maintenance cost, smoother running of trains and more comfort to the passengers. Moreover , the more number of joints would increase wear and tear of the vehicle compenents, including wheels

Through the long length of the desired, however, the length is governed by the following factors:

1. The length of the rail is so chosen that the manufacturing cost is most reasonable.2. It depends upon the transportation facilities, so only lengths of rails are possible which can be transported by longest wagons available on the railways.3. To some extent, the length is also limited by the facilities of lifting and handling, during the loading and unloading of wagons.4. More the length of the rail, more will be the gap required for expansion of rail due to temperature but, however, the expansion is not proportional to gap because fastenings check the movement of rails, so expansion gap is not limiting factor for length of rails though it affects to some extent.On Indian Railway the standard lengths are the following:Length = 12.80 m. (42ft) for B.G. (say 13m)Length = 11.89 m. (39ft) for M.G. (say 12m)

3.7 WEAR ON RAILS:

Wear is one of the prominent defects of rails. When the axle loads are abnormally heavy and the train moves with very fast speed then the concentrated stresses exceed the elastic limit resulting in metal flow; on the gap or joint the ends are battered and at the curves the occurrence of skidding, slipping and the striking of wheel flanges with rails results in wear and tear of rails.

Classification of Wear. Wear can be classified in accordance with the location and position of wear.1. On this basis of location:The wear is prominent on the following locations:

I. On sharp curvesII. On gradientsIII. On approaches to stations, where brakes are frequently aapliedIV. In tunnelsi. Where sand is used on rails to produce more friction on damp rails but on the country it gives more wear.ii. In tunnels, the gases emitting from the engine being confined attack the metal and result in wear.

2. On the basis of position of wear on rails:The following are the positions of wear on rails

A. Wear on top or head of rail.B. Wear at the ends of rails.C. Wear on the sides of the rails.

A. Wear on top or Head of rail. This type of wear occurs on straight i.e. tangent tracks and at curves.

On Tangent Tracks. The following are the factors which cause or encourage the wear on top of rail on tangent lengths:

I. Heavy axle load and its recurring impact causes the wear at the top of rails.II. Due to abrasion of rolling wheels, the rails generally get worn out at the top of rails.III. Due to fluctuations in gradients.IV. Due to corrosion of rails by the action of sea breeze, which also gives rise to wear on top of rails.

On Curves. The wear on top of rails at curves is due to the following causes :

I. Due to slipping or skidding if wheels.II. Due to effect of centrifugal force and improper superelavation, load on one rail is greater than the other. If superelevation is more or less for a given speed, the load will be more on inner or outer rail respectively .

B. Wear at the Ends of the Rails. Wear at the ends of the rails is due to high static pressure combined with impact blows. This is prominent on straight tracks only and is much more in magnitude than the wear on top of rails. This type of wear is encouraged due to following factors.

I. Due to loose fish plates and fish bolts.II. Due to heavy loads and large joint openings.III. Small wheels.IV. Poor maintenance of the track

C. Wear on sides of the Rail Head.This type of wear is only prominent when the rails are laid at curves. This wear is more than first two types of wear and is most destructive in nature. This wear occurs due to following causes.

I. At curves, there is greater thrust on inner rail, when trains run at lesser speed than equilibrium speed.II. Due to the rigidity of the wheel base.

CHAPTER 4

4.1 SLEEPERS

Sleepers are members generally laid transverse to the rail which the rails are supported and fixed, to transfer the loads from rails to the ballast and subgrade below.

FUNCTIONS OF SLEEPRES :

Sleepers perform the following functions:

i. To hold the rails to correct gauge .ii. To hold the rails in proper level or transverse tilt i.e. level in turnouts, cross-overs, etc. and at 1 in 20 tilt in straight tracks, so as to provide a firm and even support to rails.iii. To distribute the load from the rails to the index area of ballast underlying it or to the girders in case of bridges.iv. To support the rails at a proper level in straight tracks and at proper seperelevation on curves.v. They also provide means to rectify track geometry during service life.

4.2 REQUIREMENTS OF SLEEPERS:

For good performance of sleepers to fulfil the above function or objectives an ideal sleeper should possess the following characteristics:

i. The sleepers to be used should be economical, i.e. they should have minimum possible initial and maintenance costs.ii. The fittings of the sleepers should be such that they can be easily adjusted during maintenance operations such as easy lifting, packing, removal and replacement.iii. The weight of sleepers should not be too heavy or excessively light, i.e., they should have moderate weight, for ease of handling.iv. The design of sleepers should not be such that the gauge, alignment of track and levels of the rails can be easily adjusted and maintained.v. 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 the ballast underneath the sleeper.

4.3 CLASSIFICATION OF SLEEPERS:

Sleepers can be classified according to the materials used in their construction in the following categories:

1. Wooden sleepers2. Metal sleepersa. Cast iron sleepersb. Steel sleepers3. Concrete sleepersa. Reinforced concrete sleepersb. Prestressed concrete sleepers

Different types of sleepers are manufactured with the same material. They are described in the following pages:

4.4 TIMBER OR WOODEN SLEEPERS:

Wooden sleepers are regarded to be best as they fulfil almost all the requirements of an ideal sleeper. The life of timber sleepers depends upon their ability to resist (1) wear , (2) Decay, (3) Attack by vermin, i.e. white ants and (4) quality of the timber used. Following are the advantages and disadvantages of using wooden sleepers.

Advantages:

i. Timber is easily available in all parts of india.ii. Fittings for wooden sleepers are few and simple in design.iii. Wooden sleepers are easy to lay, relay, pack, lift and maintain.iv. These wooden sleepers are suitable for all types of ballast.

Disadvantages:

i. It is difficult to maintain the gauge in case of wooden sleepers.ii. Track is easily disturbed i.e, alignment maintenance is difficult.iii. Wooden sleepers have got minimum service life (12 to 15 years) as compared to other types of sleepers.iv. Maintenance cost of wooden sleepers is highest as compared to other sleepers.

4.5 METAL SLEEPERS:

Due to the growing scarcity of wooden sleepers, their high cost and short life, metal sleepers are now being widely adopted in India.

Metal sleepers are either of steel or cast iron. Cast iron is in greater use than steel for sleepers because it is less prone to corrosion. In addition to requirement given in Article 9.2, the metal sleepers should satisfy the following requirements:

I. Tamping and packing of ballast should not disturb the sleeper.II. For track circuiting, insulation should be possible.

Advantages:

i. Metal sleepers are uniform in strength and durability.ii. In metal sleepers, the performance of fittings is better and hence lesser creep occurs.iii. Metal sleepers are economical, as life is longer and maintenance is easier.iv. Gauge can be easily adjusted and maintained in case of metal sleepers.

Disadvantage:

i. More ballast is required than other type of sleepers.ii. Fittings required are greater in number, and difficult to maintain and inspection.iii. Metals, C.I. or steel, are liable to rusting/corrosion.iv. Metal being good conductor of electricity interferes with track circuiting.

4.6 CONCRETE SLEEPERS:

These sleepers were ended due to chronic shortage of good wooden sleepers and need for better design and economy of sleepers on sustainable basis.These sleepers are mainly of two types:

a. Reinforced concrete sleepers.b. Pre-stressed concrete sleepers.

Experiments have been conducted in India and abroad on concrete sleepers and it has been proved that concrete is an ideal material for the sleepers for the following reasons:

They are made of a strong homogeneous material, impervious to effects of moisture, and is unaffected by the chemical attack of atmospheric gases or sub-soil salts.

Advantages:

i. These sleepers are free from natural decay and attacks by vermin, insects,etc.ii. They have maximum life when compared to other sleepers, the life under normal conditions is 40 to 60 years.iii. This is not affected by moisture, chemical action of ballast, cinder and sub-soil salt.iv. There is no difficulty in the track- circuiting, required for electrifying the track.

Disadvantages:

i. These sleepers require pads and plugs for spikes.ii. They damage the bottom edge during the packing.iii. The scrap value is almost nil.iv. The damages to the concrete sleepers is very heavy in case of derailment.

CHAPTER 5

SUBGRADE AND EMBANKMENTS

5.1 DEFINITIONS:

1. Subgrade. Subgrade is the naturally occurring soil, which is prepared to receive tha ballast, sleepers and rails for constructing the railway track. This prepared surface is also called formation. Formation could be in embankment, level or cutting, depending upon the ground conditions.

2. Embankment. It is a raised bank of earth or other materials constructed above the natural ground. It is constructed when railways have to be carried in low grounds or valleys.

3. Cutting. The raised ground or hill is cut or excavated for providing the railway line at the required level below ground level.

4. Level. It is prepared surface which receives ballast without raising or lowering level of the ground

5. Formation. The prepared surface which is ready to receive ballast is called formation. The stability of the track depends upon the quality of the formation under it.

5.2 FUNCTIONS OF THE SUBGRADE OR FORMATION:

The formation for a track is obtained by either-constructing an embankment or providing a cutting. The height for the embankment and depth of the cutting depends upon the topography and the gradients. The top layer of embankment or bottom layer of cutting, ultimately, has to stand up to all the loads coming on the track. The subgrade materials performs the following functions:

i. It should bear the moving loads transmitted to it through the ballast with as uniform a reaction as possible.ii. It should prevent the ballast from puncturing into it.iii. To facilitate drainage, i.e,, it should drain off the water entering from its top.iv. It should provide a smooth, uniform, regular and graded surface which the ballast and the track may be safely laid.

5.3 SUBGRADE MATERIAL AND ITS IMPROVEMENT:

The selection of soils for the subgrade is not entirely within the Engineers control. A railway track extends over very long distances and different varieties of soil are likely to be encounteted. He is forced to use the subgrade available. However, if he is equipped with the knowledge of the elements of soil mechanics, he would be able to make the best use of the available subgrade, using other available materials. The following observations should be made for systematic and scientific study of subgrade soils:

i. Sub-soil survey of the entire length of the track to collect data for soils and foundations should be made.ii. The soil result along proposed alignment of track may be shown on a longitudinal section.iii. The various characteristics of soils, like moisture content, compressive strength according to Atterberg limits, chemical composition, density and shearing strength, should be studied by conducting laboratory tests.iv. Side by side, the level of underground water table should be determined, as ground water may be the cause of unstable formation.

CHAPTER 6

6.1 TRACK ALIGNMENT

The direction and position given to the centre line of the railway track on the ground is called the track alignment.

The horizontal alignment includes the straights path , its width, deviations in width and horizontal curves.

The vertical alignment of a railway track includes changes in gradients and vertical curves.

A new railway track should be aligned very carefully as improper alignment would result either in capital loss in initial cost of construction or recurring loss in maintenance and vehicle operation coast, or both. Once the track has been aligned and constructed, it is difficult to change the alignment due to increase in cost of adjoining land and construction of costly structures over railway track and at specific location by the side of railway line.

6.2 BASIC REQUIREMENTS OF GOOD ALIGNMENT:

In case of railways, the profit is not the only objective but comfort to the passengers must be given equal importance. Though the income from transportation of goods is much more than that from passenger traffic but the safety, comfort and convenience of passengers are always kept in view. An ideal alignment should fulfil the following requirements:

1. Purpose of track. The alignment of the track should be done keeping in view the basic purpose or purposes, it is going to serve. In general, the railway serve the following purposes:

i. Transportation Services. Railways carry the passenger traffic, and goods traffic, local as well as through.ii. Political and Strategic. Sometimes it becomes essential to construct a railway line to connect two points for defence purposes so that in case of emergency, armies within the country can be transferred from one place to another.iii. To open up New Tracks. It may be necessary to align new tracks for the land, whose resources are not yet tapped.

2. Feasibility. For aligning a railway line, it is necessary so carrying feasibility study so that the proposed track alignment melts all technical requirements and also fits in well the general planning of the country.

3. Economy. The track alignment will be economical when following factors are given due consideration:

i. All other things being equal, the shortest and the most direct route between two joining points is the cheapest. Though , there may be several practical considerations which would cause a deviation from the shortest route.ii. The initial construction cost should be minimum. This can be achieved by avoiding loose earth slopes, rock-cuttings, drainage crossings by aligning the track on watersheds etc. if feasible,

4. Safety. The track should be so aligned that it gives safety to traffic operations or in other words the passengers and goods traffic can be transported without any chance of accident or derailment.

6.3 FACTORS IN SELECTION OF GOOD-ALIGNMENT:

Though the direct shortest route is the most economical but is rarely possible due to various practical difficulties such as intermediate obstructions, steep gradients within the shortest route, construction and maintenance problems, etc. Moreover,it may be necessary to deviate from the shortest route to connect obligatory points.

An alignment, which is economical in the initial cost, may not prove most economical in maintenance or vehicle operation cost or both. It is also possible that shortest route may be costlier than other routes, when different alternatives are tried from construction point of view. Thus , it may be concluded that all the requirements cannot be fully justified simultaneously. For satisfying most of the requirements, the following factors in selection of good alignment, require due consideration:

1. Obligatory or controlling points. 2. Position 3. Gauge-selection 4. Geometric standards 4. Topography of the country, 5. Other considerations.

1. Obligatory or controlling Points. These are the points which govern the alignment of a railway track. These points can be mainly classified into two categpries:

i. Points through which a track must pass.ii. Points through which a track should not pass.

2. Traffic-its Position, Nature and Amount. The position of traffic sources furnishes control points for general location of the alignment.The nature of traffic and potential volume of traffic govern the type of construction to justify the revenus. So it is essential to the track.

3. Gauge Selection. This has already been discussed in brief, it can be said that though the increase in width of gauge increases initial cost but it also increases load carrying capacity and the speed of the trains.

4. Geometric Standards. An engineer should design the location of a new line considering the following geometric elements, which would give economical combination of construction and operation costs.i. it should be kept in view that the performance of locomotives as also efficiency depends upon varying conditions of gradients, speed, loading and method of traction usedii. ruling gradient and minimum permissible radius of the curve must be considered while making the alignment of the track as it limits the weight and length of trains and thus affects the cost of operation.

CHAPTER 7

GEOMETRIC DESIGN OF THE TRACK

7.1 NECESSITY OF GEOMETRIC DESIGN OF A RAILWAY TRACK:

Most of the train derailments are due to the following reasons:

(A) Track defects (B) Vehicular (C) Operational defects.

The Civil Engineer is mainly concerned with track defects. He should be aware the track defects and how to remove these defects so that no derailment takes place. Railway track should be designed, suiting to load and speed of the train, and meeting the safety and economy requirements.

A train may derail on the straight track due to the following defects in the track:

(A) Defective cross-levels, (B) Defective alignment

(C) Low joints (D) defective gauge

In addition to this, on curved tracks, the derailment may occur due to additional following causes:

(A) Improper superelevation, (B) Improper radius of the curve,

(C) Improper speed (D) Unequal distribution of loads on two rails.

Cross level, alignment, gauges and joints have already been discussed in previous chapters, and elements of turnouts will be discussed in the chapter that follows. In this chapter, the study will be confined to the following elements of a railways track:

(1) Gradients and grade compensation (2) Speed of train

(3) Radius or Degree of the curve (4) Cant of Superelevation.

(5) Curves (6) Widening of Gauge on curves.

7.2 SUPERELEVATION OR CANT:

When a train moves round a curve, it is subjected to a centrifugal force acting horizontally at the centre of gravityof each vehicle radially away from the centre of the curve. This increases the weight on the outer rail. To counteract the effect of centrifugal force. The level of the outer rail is raised above the inner rail by a certain amount to introduce the centripetal force. This raised elevation of outer rail above the inner rail at a horizontal curve is called superelevation. The term cant is frequently used as a synonym for superelevation but truly speaking cant should be used to represent the angle of a transverse slope.

Mathematically speaking, the object of providing the superelevation, is to make the force of reaction equal at both the rails and perpendicular to the track and thus equalize the weight on either rail. Superelevation is denoted by e.

Objects of providing superelevation. The following are the objects of providing superelevation on curves:

1. To introduce the centripetal force for counteracting the effect of centrifugal force. This will result in the faster movement of train on curves. This will also prevent derailment and reduce the side wear and creep of rails.

2. To provide equal distribution of wheel loads on two rails so that there is no tendency of track to move out of position due to more load on outer rail. This reduces the wear of rails, equipment and results in saving in maintenance cost.

7.3 CURVES:

Necessity. Though it is desirable to have a straight track and it is the ideal condition but the use of curves becomes absolutely necessary for a change in the alignment or gradient. Simple curves are introduced to ease off the changes. The use of curves it warranted in the following conditions:

i. To bypass the natural or artificial obstacles.ii. To provide easier gradients by diversions from the straight route.iii. To route the line through areas having traffic potentialitiesiv. To balance the earth work in excavation and cutting thereby minimising the cost of construction.