Unit ii railways

Railway

1. RAILWAYS UNIT II

2. Railway A permanent way. Transport Passengers and Goods.

3. Railway Engineering Design, Construction & Maintenance of Railway Tracks Safe & Efficient movement of Trains. Railway and Roads – Ground Transportation.

4. History of Indian Railway First Indian Railway was opened on 16 th April 1853. One Steam Engine Four Coaches Bombay to Thane (34 km) Owner- Military Engineers of the East India Company, later - British Indian Army Indian Railway- Indian State Owned Enterprise owned and operated by Govt. of India through Ministry of Railway.

5. Roadways V/S Railways Suitable for only from one station to another station. Load carrying capacity is more than roadways. Suitable for long distance Maintenance cost is more. Limitation on the steeper gradient Suitable for all types of traffic. Load carrying capacity is less. Suitable for any distance. Maintenance cost is less. Suitable for steeper gradients.

6. Feasibility Studies An assessment of the practicality of a proposed plan or method. Preliminary Study

7. Large or complex project / doubt or controversy regarding proposed development To determine if the construction is feasible To establish the technical and financial basis for the rest of the design and executing process of the works. In the Past feasibility studies for Railway projects have been developed on ad hoc basis – no standardize approach. It results in High Risk Failure, Project runs very late, widely over budget.

8. Permanent Way Combination of rails, fitted on sleepers and resting on ballast and sub-grade is called the railway track or permanent way.

9. Component parts of a permanent way Subgrade Ballast Sleepers Rails Fixture and Fastening

10. Component parts of a permanent way

11. Component parts of a permanent way In a permanent way, rails are joined either by welding or by using fish plates and are fixed with sleepers by using different types of fastenings. Sleepers are properly placed and packed with ballast. Ballast is placed on the prepared subgrade called formation.

12. Requirements of an ideal permanent way ( i ) The gauge of the track should be uniform and correct. (ii) Both the rails should be at the same level in a straight track. (iii) On curves proper superelevation should be provided to the outer rail. (iv) The permanent way should be properly designed so that the load of the train is uniformly distributed over the two rails.

13. Requirements of an ideal permanent way (v) The track should have enough lateral strength so that it can maintain its stability even with variation in temperature and other factors. (vi) The radii and super elevation, provided on curves, should be properly designed. (vii) The track must have certain amount of elasticity to absorb the shocks and vibrations of running trains.

14. Requirements of an ideal permanent way (viii) All joints, points and crossings should be properly designed. (ix) Drainage system of permanent way should be perfect so that the stability of the track is not affected by water logging. (x) All the components of permanent way should satisfy the design requirements. (xi) It should have adequate provision for easy renewals and repairs.

15. Track Structure The maximum distance between the running faces of the two rails of a permanent way is called GAUGE. The track standards had been laid down in 1973 after review by a committee of Directors, Chief Engineers. These track standards were reviewed based on railway reforms committee recommendations and on the recommendations of 60 th track standard committee

16. Track Structure The railway board accordingly laid down in 1985 the track standards for various routes which were made applicable for new works included in 1986-87 Budget. These triple gauges exhibit the hierarchical importance of the rail routes.

17. Hierarchy The double track broad gauge today linking the metropolitan cities and major ports comes on the top of the list Followed by single track broad gauge branch line on peripheral trunk routes, Meter gauge double track lines, Meter gauge single track routes and Narrow gauge rail lines.

18. Gauge width Broad gauge is 1.44 meters in width. Meter gauge is 1 meter which, the name itself denotes. Narrow gauge is used in mountain or hill trains which is less than a meter and it's width is 0.79 meters.

19. Group `A'-For a sanctioned speed of 160 km. per hour The minimum rail section to be adopted will be 60 Kg. in section having traffic density of over 20 GMT and 52 Kgs in other sections. The minimum sleeper density shall be 1,660 numbers per Km. The ballast cushion shall be 30 cm.

20. Group `B'-For a sanctioned speed of 130 km. per hour The minimum rail section to be adopted will be 60 Kg. in sections having traffic density of over 20 GMT and 52 Kg. in other sections. The minimum sleeper density shall be M+7. The ballast cushion shall be 25 cm.

21. Group `C'-Suburban Sections The minimum rail section to be adopted will be 60 Kg. in sections having traffic density of over 20 GMT and 52 Kg. in other sections. The minimum sleeper density shall be M + 7. The ballast cushion shall be 25 cm.

22. Group `D'-Where the maximum sanctioned speed is 100 Kms /hour, as at present The minimum rail section to be adopted will be 60 Kg in sections having traffic density of over 20 GMT, 52 Kg. in sections having traffic density from 10 to 20 GMT and 44.5 Kg in sections having traffic density of less than 10 GMT. The minimum sleeper density shall be M + 7 in sections having traffic density above 10 GMT and M + 4 in sections having traffic density below 10 GMT. The ballast cushion shall be 20 cm.

23. Double headed rails(D.H. Rails) The rails having their head and foot of same dimensions are known as double headed rail (D.H.) The idea behind using these rails was that when the head had worn out due to rubbing action of wheels, the rails could be inverted and reused. But by experience it was found that their foot could not be used as running surface because it also got corrugated under the impact of wheel loads.

24. Double headed rails(D.H. Rails)

25. Bull headed rails( B.H.Rails )   The rail section whose head dimensions are more than that of their foot are called bull headed rails. In this type of rail the head is made little thicker and stronger than the lower part by adding more metal to it. These rails also require chairs for holding them in position. Bull headed rails are especially used for making points and crossings.

26. Bull headed rails( B.H.Rails )  

27. Flat Footed Rails The rail sections having their foot rolled to flat are called flat footed. It was initially thought that the flat footed rails could be fixed directly to wooden sleepers and would eliminate chairs and keys required for the B.H. rails. But later on, it was observed that heavy train loads caused the foot of the rail to sink into the sleepers and making the spikes loose. To remove this defect, steel bearing plates were used in between flat footed rails and the wooden sleeper. These rails are most commonly used in India.

28. Flat Footed Rails

29. DESIGN OF RAIL The rail is designated by its weight per unit length. In metric units it is in kg per meter. A 52 kg/m rail denotes that it has a weight of 52 kg per meter. The weight of a rail and its section is decided after considerations such as the following: (a) Heaviest axle load (b) Maximum permissible speed (c) Depth of ballast cushion (d) Type and spacing of sleepers (e) Other miscellaneous factors

30. DESIGN OF RAIL The standard rail sections in use on Indian Railways are 60 kg, 52 kg , 90 R, 75 R, 60 R and 50 R. The two heavier rail sections, 60 kg and 52 kg, were recently introduced and are designated in metric units. Other rails are designed as per the revised British Standard specifications and are designated in FPS units though their dimensions and weight are now in metric units. In the nomenclature 90 R, 75 R, etc., R stands for revised British specifications. The brand marks on the rails are to be rolled in letters at least 20 mm in size and 1.5 mm in height at intervals of 1.5 to 3.0 m.

31. DESIGN OF RAIL Every rail rolled has a brand on its web, which is repeated at intervals. As per IRS–T–12–88, the brand marks are as follows: IRS-52 kg – 710 – TISCO – II 1991 ® OB. The definitions for the various abbreviations are as follows: (a) IRS-52-kg: Number of IRS rail section, i.e., 52 kg (b) 710: Grade of rail section, i.e., 710 or 880 (c) TISCO: Manufacturer’s name, e.g., Tata Iron and Steel Co. (d) II 1991: Month and year of manufacture (February 1991) (e) ®: An arrow showing the direction of the top . (f) OB: Process of steel making, e.g., open hearth basic (OB)

32. SLEEPERS Sleepers are transverse members of the track placed below the rails to support and fix them in position. They transmit wheel load from the rails to the ballast.

33. FUNCTIONS OF SLEEPERS To hold the rails to proper gauge. (ii) To transfer the loads from rails to the ballast. (iii) To support and fix the rails in proper position. (iv) To keep the rails at a proper level in straight tracks and at proper super elevation on curves. (v) To provide elastic medium between the rails and the ballast. (vi) To provide stability to the permanent way on the whole.

34. REQUIREMENTS OF GOOD SLEEPERS ( i ) The sleepers should be sufficiently strong to act as a beam under loads. (ii) The sleepers should be economical. (iii) They should maintain correct gauge. (iv) They should provide sufficient bearing area for the rail.

35. REQUIREMENTS OF GOOD SLEEPERS (v) The sleepers should have sufficient weight for stability. (vi) Sleepers should facilitate easy fixing and taking out of rails without disturbing them. (vii) They should facilitate easy removal and replacement of ballast. (viii) They should not be pushed out easily of their position in any direction under maximum forces of the moving trains.

36. REQUIREMENTS OF GOOD SLEEPERS ix) They should be able to resist impact and vibrations of moving trains. (x) They should be suitable to each type of ballast.

37. TYPES OF SLEEPERS

38. RCC

39. CAST IRON SLEEPERS

40. FASTENINGS Fixtures and fastenings are fittings required for joining of rails end to end and also for fixing the rails to sleepers in a track.

41. FUNCTIONS OF FIXTURES AND FASTENINGS ( i ) To join the rails end to end to form full length of track. (ii) To fix the rails to sleepers. (iii) To maintain the correct alignment of the track. (iv) To provide proper expansion gap between rails. (v) To maintain the required tilt of rails. (vi) To set the points and crossings in proper position.

42. TYPES OF FIXTURES AND FASTENING 1. Fish plates 2. Bearing plates 3. Spikes 4. Chairs 5. Bolts 6. Keys 7. Anticreepers

43. Fish plates A fish plate is a metal or wooden plate that is bolted to the sides at the ends of two rails or beams, to join them.

44. Spikes A rail spike (also known as a cut spike or crampon) is a large nail with an offset head that is used to secure rails and base plates to railroad ties in the track.

45. Bearing plate These are the plates which are provided in between the flat footed rails and wooden sleepers.

46. Bolts Bolts are used for connecting fish plates to the rails at rail joint, bearing plates and chairs to wooden sleepers etc.

47. Chairs Cast iron chair (C.I chairs). Slide chairs

48. Keys These are small tapered pieces of timber or steel used to fix rails to chairs on metal sleepers. Keys are of two types : ( i ) wooden keys: Wooden keys are small straight or tapered pieces of timber. These are cheap and Easily prepared. These are not strong and become loose under vibrations. These require frequent maintenance. Wooden keys are not used now-a days in Indian Railways.

49. Keys ii) Metal keys : Metal keys are small tapered or spring like pieces of steel. These keys are much more durable than wooden keys. Metal keys are of two types: ( i ) Stuart`s key and (ii) Morgan key

50. Coning of wheels "Coning of wheels" is what allows a train to take a turn without slipping off its tracks. The thread of the wheels of a railway vehicle are not flat but sloped like a cone. The wheels generally, remain central on a straight and level surface and the circumference of the threads of both the vehicle are equal.

51. Coning of wheels However on a curve , the outer wheel has to negotiate more distance as compared to the inner wheel. Due to centrifugal force on a curve, the circumference of the thread of the outer wheel thus becomes greater than that of the inner wheel. This helps the outer wheel to travel longer distance than the inner wheel.

52. Coning of wheels Disadvantages i ) The outer rail will have more pressure while the inner rail will have lesser pressure. (ii) Owing to the centrifugal strength, the parallel components incline to turn the rail out and gauge has broadening tendency. (iii) Due to this condition if the voids sleepers have no base plate beneath the edge of the rail they will be damaged.

53. Coning of wheels

54. Tilting of Rails If the rails are laid flat, coning of the wheels will subject the rails to eccentric loading . Tilting is achieved by using inclined base plates. The slope of the base plate is 1 in 20 which is the slope of the coned surface of the wheel.

55. Tilting of Rails Advantages of Tilting of Rails: The tilting of rails increases the life of sleepers and rails. It maintains the gauge properly. The wear of the head of the rail is uniform due to tilting of rails.

56. Tilting of Rails

57. Tilting of Rails

58. BALLAST Ballast is the granular material usually broken stone or any other suitable material which is spread on the top of railway formation and around the sleepers.

59. FUNCTIONS OF BALLAST ( i ) To hold the sleepers in position and preventing the lateral and longitudinal movement. (ii) To distribute the axle load uniform from sleepers to a large area of formation. (iii) To provide elasticity to the track. It acts as an elastic mat between subgrade and sleepers.

60. FUNCTIONS OF BALLAST (iv) To provide easy means of maintaining the correct levels of the two rails in a track. (v) To drain rain water from the track. (vi) To prevent the growth of weeds inside the track..

61. REQUIREMENT GOOD BALLAST i ) It should have sufficient strength to resist crushing under heavy loads of moving trains. (ii) It should be durable enough to resist abrasion and weathering action. (iii) It should have rough and angular surface so as to provide good lateral and longitudinal stability to the sleepers. (iv) It should have good workability so that it can be easily spread of formation.

62. REQUIREMENT GOOD BALLAST (v) It should be cheaply available in sufficient quantity near and along the track. (vi) It should not make the track dusty or muddy due to its crushing to powder under wheel loads. (vii) It should allow for easy and quick drainage of the track. (viii) It should not have any chemical action on metal sleepers and rails.

63. TYPES OF BALLAST Broken stone. Gravel Sand Ashes or cinders Kankar Murum Blast furnace slag Brick ballast Selected earth

64. BROKEN STONE  This is the best type of ballast as it possesses all the characteristics of a good ballast. It holds the track to correct alignment and gradient due to its high interlocking action. The stones which are non porous, hard and do not flake on breaking should be used. Igneous rocks such as granite, quartzite and trap make excellent ballast. This type of ballast is used for high speed tracks.

65. BROKEN STONE ADVANTAGES a. It is hard and resist crushing under heavy loads. b. It has angular and rough surface and hence gives more stability to the sleepers. c. Its drainage property is excellent. DISADVANTAGES (a) It is expensive. (b) It is not so easily available

66. GRAVEL Gravel is the second best material for ballast. This is obtained either from river beds or from gravel pits and has smooth rounded fragments. Gravel obtained from pits usually contains earth which should be removed by washing. Gravel obtained from river beds is screened and required size gravel is used. Larger size gravels are broken into required size. Round edges gravels are broken to increase their interlocking action.

67. GRAVEL ADVANTAGES (a) Gravel is cheaper than stone ballast. (b) The drainage property of gravel excellent. (c) It holds the track to correct alignment and gradient. (d) It is easy to use gravel ballast than stone ballast at certain places where formation is unstable. DISADVANTAGES (a) It requires screening before use due to large variation in size. (b) Gravel obtained from pits requires washing. (c) Due to round faces the packing under sleepers is loose. (d) Gravel easily roll down due to vibrations.

68. Pre-stressed concrete sleepers Pre-stressed concrete sleepers are now-a-days extensively used in Indian Railways. These sleepers have high initial cost but are very cheap in long run due to their long life. In these sleepers, high tension steel wires are used. These wires are stretched by hydraulic jack to give necessary tension in the wires. The concrete is then put under a very high initial compression. These sleepers are heavily damaged in case of derailment or accidents of trains.

69. Welding of Rail Joint The purpose of welding is to join rail ends together by the application of heat and thus eliminate the disadvantages of fish plate rail joints. There are four welding methods used on railways. (a) Gas pressure welding (b) Electric arc or metal arc welding (c) Flash butt welding (d) Thermal welding

70. PURPOSE To increase length of rail by joining two or more rails. To repair the worn out or damaged rails and thus increase their life. To build up worn out points and rails on the sharp curves. To build up the burnt portion of rail head caused due to slippage of wheels over the rail or other defects or spots in rail steel.

71. ADVANTAGES (1)It satisfies the conditions of a perfect joint and hence increases the life of the rail and reduces the maintenance cost by @ 20 to 40%. (2) It reduces the creep as the length of rail increases. (3) Expansion effect due to temperature is also reduced which also reduces the creep.

72. ADVANTAGES (6) Increase the life of rails due to decrease wear. (7) Facilitates track circuiting on electrified tracks. (9) Welded rails on curves is under investigation, Maximum curve radius may be welded depending upon resistance a lateral displacement of track. (10) Long rail lengths dampen the intensity of high frequency vibrations due to moving length.

73. Electric Arc welding In this method current is passed through rail as well as through electrode. As electrode approaches the rail an electric arc is formed and with the heat electrode gets melted and the molten metal deposits on the rail, providing a firm bond. Easy to handle This consists of an engine, generator and some accessories.

74. Electric Arc welding Used for building up worn out points and crossing damaged rails and other small welding operations.

75. Oxy-acetylene welding Intense heat is produced by combining the oxygen and acetylene gas which melts electrode and deposits the molten metal on rails. This plant consists of two cylinders, best in mobility point of view. Used for repairing worn out or damaged part of points and crossing. This is specially useful for cutting of steel.

76. Flash welding Powerful current is passed through two rails, here ends of which are to be joined together. Heating upto required temperature they are brought in contact resulting in flash then current is stopped and rails are pressed together under a pressure of 20T Most satisfactory. This method of welding involves heavy welding plant and that too immobile and hence uneconomical for small jobs at site.

77. Chemical or Termite Welding This involves the use of chemical, aluminum and iron oxide. Aluminum and iron oxide is mixed in a powder form and ignited. On ignition the chemical reaction takes place produces intense heat because this reaction is exothermic in nature. After reaction the Fe gets separated and is deposited in the gap of rail ends which are preheated.

78. Chemical or Termite Welding Actually these two ends with the chemical mixture in between the gap are entrapped in mould to prevent the flow of mixture a shown in fig.

79. Short Welded Rails (SWR) Technical advantage that a welded track possess over the fish plated track necessitated the development of welded joints of rail. This first stage of development in this direction is short welded rails (S. W. R.). A short welded rails is a welded rail which contracts and expands throughout its entire length due to temperature variations.

80. Long Welded Rails (LWR) Long welded rails is a welded rails of which the central part does not undergo any longitudinal movement due to temperature variations. The concept behind development of long welded rails is the locking up of stresses which resists longitudinal movement of rail.

81. Continuously Welded Rails (CWR) On Indian Railways the length of long welded rails has been limited to one km only because of panels upto this length are considered convenient for the purpose of laying distressing and from maintenance point of view. The welded panels longer than one km that have been tried by Indian railways and are called as Continuously Welded Rails.

82. Points crossings and turnouts Points and crossings are provided to help for transferring railway vehicles from one track to another. The tracks may be parallel to, diverging from, or converging with each other. These are necessary because the wheels of railway vehicles require special arrangement in order to navigate their way on the rails.

83. Points crossings and turnouts The points or switches aid in diverting the vehicles and the crossings provide gaps in the rails so as to help the flanged wheels to roll over them. Furnace is used at the bottom of rails for eating the ends, After the mixture is solidifies the mould is removed and surface girding is done. Used in renewal of rails. This plant is mobile in nature and can be used site for welding of rails

84. Switches / Points A set of points or switches consists of the following main constituents (a) A pair of stock rails, AB and CD, made of medium-manganese steel. (b) A pair of tongue rails, PQ and RS, also known as switch rails, made of medium-manganese steel. The tongue rails are machined to a very thin section to obtain a snug fit with the stock rail. The tapered end of the tongue rail is called the toe and the thicker end is called the heel.

85. Switches / Points (c) A pair of heel blocks which hold the heel of the tongue rails at the standard clearance or distance from the stock rails. (d) A number of slide chairs to support the tongue rail and enable its movement towards or away from the stock rail. (e) Two or more stretcher bars connecting both the tongue rails close to the toe , for the purpose of holding them at a fixed distance from each other. (f) A gauge tie plate to fix gauges and ensure correct gauge at the points.

86. Switches / Points

87. Crossing A crossing or frog is a device introduced at the point where two gauge faces cross each other to permit the railway vehicle to pass from one track to another. Component Parts of a Crossing ( i ) A vee piece (ii) A point rail (iii) A splice rail (iv) Two check rails (v) Two wing rails (vi) Heel blocks at throat, nose and heel of crossing (vii) Chairs at crossing, at toe and at heel.

88. Two rails, the point rail and splice rail, which are machined to form a nose. The point rail ends at the nose, whereas the splice rail joins it a little behind the nose. Theoretically, the points rail should end in a point and be made as thin as possible, but such a knife edge of the point rail would break off under the movement of traffic. The point rail, therefore, has its fine end slightly cut off to form a blunt nose, with a thickness of 6 mm (1/4").

89. The toe of the blunt nose is called the actual nose of crossing (ANC) and the theoretical point where gauge faces from both sides intersect is called the theoretical nose of crossing (TNC). The ‘V’ rail is planed to a depth of 6 mm (1/4") at the nose and runs out in 89 mm to stop a wheel running in the facing direction from hitting the nose.

90. REQUIREMENTS OF IDEAL CROSSING ( i ) Crossing assembly should be rigid enough to withstand severe vibrations. (ii) Wing rails and nose of crossing should be able to resist heavy wear due to movement of wheels, hence should be manufactured of special steel (alloy steel). (iii) The nose of crossing should have adequate thickness to take all stresses acting on the crossing.

91. TYPES OF CROSSINGS Crossings can be classified as follows: 1. On the basis of shape of crossing (a) Square crossing (b) Acute angle or V-crossing or Frog (c) Obtuse angle or Diamond crossing 2. On the basis of assembly of crossing (a) Ramped crossing (b) Spring or movable crossing.

92. Square Crossing Square crossing is formed when two straight tracks of same or different gauge, cross each other at right angles. This type of crossing should be avoided on main lines because of heavy wear of rails.

93. Acute Angle Crossing Acute angle crossing is formed when left hand rail of one track crosses right hand rail of another track at an acute angle or vice versa. This type of crossing consists of a pair of wing rails, a pair of check rails, a point rail and a splice rail. This crossing is widely used.

94. Obtuse Angle Crossing Obtuse angle crossing is formed when left hand rail of one track crosses right hand rail of another track at an obtuse angle or vice versa. This type of crossing consists mainly of two acute angle and two obtuse angle angle crossings. This is also called Diamond crossing.

95. TURNOUT Turnout is an arrangement of points and crossings with lead rails by which trains may be diverted from one track to another moving in the facing direction. A turnout is left handed or right handed as the train taking the turnout in the facing direction is diverted ti the left or right of the main line.

96. Component parts of a Turnout Following are the component parts of a turnout ( i ) A pair of tongue rails (ii) A pair of stock rails (iii) Two check rails (iv) Four lead rails (v) A vee crossing

97. (vi) Slide chairs (vii) Stretcher bar (viii) A pair of heel blocks (ix) Switch tie plate or gauge tie chair (x) Parts for operating points – Rods, cranks, levers etc. (xi) Locking system which includes locking box, lock bar, plunger bar etc. ( i ) A Pair of Tongue Rails: The tongue rails along the stock rails in a turnout form a pair of points or switches. The tongue rails facilitate the diversion of a train from the main track to a branch track.

98. ii) A Pair of Stock Rails: They are the main rails to which the tongue rails fit closely. The stock rails help in smooth working of tongue rails. (iii) Two Check Rails: Check rails are provided adjacent to the lead rails, one in main track and another in branch track. These rails check the tendency of wheels to climb over the crossing. (iv) Four Lead Rails: Outer straight lead rail, outer curve lead rail, inner straight lead rail and inner curve lead rail are the four lead rails provided in a turnout. The function of these rails is to lead the track from heel of switches to the toe of crossing.

99. (v) A Vee Crossing: a Vee crossing is formed by two wing rails, a point rail and a splice rail. It provides gaps between the rails so that wheel flanges pass through them without any obstruction. (vi) Slide Chairs: Slide chairs are provided to support the tongue rail throughout their length and to allow lateral movement for changing of points.