SLEEPERS - RAILWAY ENGINEERING

I am a student of civil engineering of Aliah Univeristy. Me and my friends have prepared this ppt on railway sleepers.

1. RAILWAY ENGINEERING TOPIC RAILWAY SLEEPERS Presented By Krishnendu B iswas –CEN204007 Rishika Chanda - CEN204005 Akashdeep Dey - CEN204004 Sahil Ahamed - CEN204003 Imdadul Hassan Mallick –CEN204002 Aliah University Action Area II-A, 27, NewTown , Kolkata-700160 Department of Civil Engineering

2. “When a train goes through a tunnel and it gets dark, y ou don’t throw away the ticket and jump off. You sit still and trust the Engineer.’’ - Corrie ten Boom RAILWAY ENGINEERING

3. TABLE OF CONTENTS

4. What is a railway sleepers? SLEEPERS Railway sleepers are the components on which the rails are arranged with proper gauge. These sleepers generally rests on ballast and is also called as ties in some regions. The load from rails when train passes, is taken by these sleepers and is distributed it to the ballast. Sleepers are members generally laid transverse to the rails on which the rails are supported and fixed, to transfer the loads from rails to the ballast and subgrade below .

5. SLEEPERS

6. SLEEPERS Sleepers

7. SLEEPERS

8. FUNCTIONS OF SLEREPERS To hold the rails to correct gauge (exact in straight and flat curves, loose in sharp curves and tight in diamond crossings). 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. To act an elastic medium in between the ballast and rails to absorb the blows and vibrations of moving loads. To distribute the load from the rails to the index area of ballast underlying it or to the girders in case of bridges.

9. FUNCTIONS OF SLEREPERS To support the rails at a proper level in straight tracks and at proper superelevation on curves. Sleepers also add to the longitudinal and lateral stability of the permanent track on the whole. They also provide means to rectify track geometry during service life.

10. RAIL, SLEEPERS & BALLAST Sleepers Ballast Rails

11. REQUIREMENT OF SLEEPERS An ideal sleeper should possess the following characteristics: The sleepers to be used should be economical, i.e., they should have minimum possible initial and maintenance costs. 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 . The weight of sleepers should not be too heavy or excessively light.

12. REQUIREMENT OF SLEEPERS 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. The sleepers should be capable of resisting shocks and vibrations due to passage of heavy loads of high-speed trains. The insulation of rails should be possible for track circuiting , if required, through sleepers. An ideal sleeper should also have an anti-sabotage and anti-theft qualities

13. RAILWAY TRACK CIRCUITING Railway Track Circuiting

14. CLASSIFICATION OF SLEEPERS

15. CLASSIFICATION OF SLEEPERS Wooden Sleepers Metal Sleepers Concrete Sleepers

16. TIMBER OR WOODEN SLEEPERS

17. 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 Wear, Decay, Attack by Vermin, i.e., white ants and Quality of the timber used.

18. TIMBER OR WOODEN SLEEPERS Timber is easily available in all parts of India. Fittings for wooden sleepers are few and simple in design . These sleepers are able to resist the shocks and vibrations due to heavy moving loads and also give less noisy track. Wooden sleepers are easy to lay, relay, pack, lift and maintain . These wooden sleepers are suitable for all types of ballast . They are best for track-circuited operations and moreover, wooden sleepers are over-all economical . Advantages

19. TIMBER OR WOODEN SLEEPERS The sleepers are subjected to wear, decay, attack by white ants, spike killing, warping, cracking, end splitting, rail cutting, etc. It is difficult to maintain the gauge in case of wooden sleepers. Track is easily disturbed , i.e.. alignment maintenance is difficult. Wooden sleepers have got minimum service life (12 to 15 years) as compared to other types of sleepers. Maintenance cost of wooden sleepers is highest as compared to other sleepers Disadvantages

20. DEFECTS OF WOODEN SLEEPERS

21. TYPE OF WOODEN SLEEPERS Timbers most commonly used for sleepers in India are that of sal and teak .

22. TREATMENT OF WOODEN SLIPPERS The life of the sleepers can be increased from 30% to 50% for treated sleepers over untreated sleepers. ‘U’ or Untreated sleepers comprising of all the sleepers made of wood from naturally durable species in other hand ‘T’ or Treated sleepers consisting of the rest of the sleepers. Timber has millions of minute cells. The cells contain juices, and removal of the juices and filling up the cells with a preserving solution (salt solution or oil) is known as treatment of sleeper or wood.

23. SEASONING OF SLEEPERS Artificial Seasoning Artificial seasoning in kiln This is a controlled method of seasoning the timber, normally used in the USA and other advanced countries, under conditions of temperature and relative humidity, which are in the range of natural air seasoning. Boulton or boiling under vacuum process This is a process in which unseasoned wood is treated with hot preservative to remove the moisture content. This is adopted in the Naharkatia depot.

24. SEASONING OF SLEEPERS Air Seasoning Air seasoning this is the method adopted extensively for the seasoning of wooden sleepers in India . The sleepers are stacked in the timber yard and a provision is made for enough space for the circulation of air in between the sleepers. The sleepers are stacked in any one of the following ways: (a) One and nine method (b) Close crib method (c) Open crib method One and Nine method & Open crib method Close crip

25. COMPOSITE SLEEPER INDEX This is an index to determine the suitability of a particular timber for use as a sleeper. This index measures the mechanical strength of timber , derived from its composite properties of strength and hardness. The C.S.I. is calculated from the relation :   S= Strength Index, both for green and dry timber at 12% moisture content. H= Hardness Index, both for green and dry timber at 12% moisture content .

26. COMPOSITE SLEEPER INDEX Minimum value of C.S.I. prescribed on Indian Railways is as follows: Type of Sleepers Minimum C.S.I. Track Sleepers 783 Crossing Sleepers 1352 Bridge Sleepers 1455

27. WOODEN SLEEPERS ON BRIDGES L G Guard rail Bearing plates Sleepers Girder or joists D Bearings Abutments or pipes Wooden Sleepers on Bridges

28. SLEEPER DIMENSIONS ON BRIDGES Description B.G. M.G. N.G. Length (L)- wooden sleepers D+30 cm (Min. 2.4 m) D+30 (min. 1.65 m) D+30 cm Minimum depth Excluding fittings 15 cm 12.5 cm (15 cm x R) 12.5 cm Maximum clearance/spacing between the sleepers 50 cm 30 cm 25 cm

29. SLEEPERS 4 .10 Size of Timber Sleepers Gauge Length (cm) Width (cm) Depth (cm) Bearing Area Per Sleepers (sq. m) B.G. 275 25 12.5 0.465 M.G. 180 20 11.5 0.31 N.G. 150 18 11.5 0.209 For bridges and points and crossings longer sleepers of thicker section viz 25 cm x 15 cm or 25 cm x 18 cm are used on the railways. Bearing area under each rail.= Bearing length under each rail x width of sleeper. For B.G., Bearing area under each rail = 0.9 m x 0.25 m= 0.225 sq.m Thus, bearing area per sleeper = 2x0.225= 0.450 sq.m For Girder bridges with open deck, thicker section of sleepers are used and their length also is 30 cm longer than the distance between the outside edges of the parallel girders.

30. CHECK SLEEPERS When timber sleepers become spike killed , their serviceable portions are cut and used with tie bars in station yards (i.e. locations of compulsory stoppage). They are not used on a track having running traffic . Sometimes they are used on important bridges with suitable tie bars . Through sleepers are also used at suitable spacings.

31. 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.

32. METAL SLEEPERS

33. METAL: CAST IRON SLEEPERS Cast Iron Railway sleepers

34. METAL: STEEL SLEEPERS Steel Railway Sleepers

35. METAL SLEEPERS REQUIREMENTS They (metal sleepers) should bear the tensile and compressive stresses which come on to them. They should provide sufficient area for rails , i.e., area on ballast should be at least equal to that of wooden sleepers. Tamping and packing of ballast should not disturb the sleeper. For track circuiting, insulation should be possible. Metal sleepers should be overall economical as compared to wooden sleepers.

36. METAL SLEEPERS REQUIREMENTS The design of metal sleepers should be such that they provide (a) Ease in fixation and removal of rails without disturbing the sleepers. (b) Ease in pushing out the sleepers and replacing them without disturbing the rail and the ballast. Metal sleepers should provide sufficient grip on the rail and ballast to prevent the dislocation of track due to shocks and vibrations, caused by heavy loads.

37. METAL SLEEPERS Metal sleepers are uniform in strength and durability . In metal sleepers, the performance of fittings is better and hence lesser creep occurs. Metal sleepers are economical , as life is longer and maintenance is easier Gauge can be easily adjusted. They have good scrap value . Advantages

38. METAL SLEEPERS More ballast is required than other type of sleepers. Fittings required are greater , difficult to maintain and inspection. Metals, C.I., or steel, are liable to rusting/corrosion . Metal being good conductor of electricity interferes with track circuiting . Metal sleepers are unsuitable for bridges , level crossings and in case of points and crossings . Disadvantages

39. CAST IRON SLEEPERS Cast iron sleepers have been extensively used in India and on a small scale in South America . They are of the following types:

40. CI POT OR BOWL SLEEPERS Cross Section and Longitudinal view of Pot Sleepers

41. CI PLATE SLEEPERS This sleeper consists of rectangular plates about 86.5 cm x 30.5 cm in size with 30.5 cm side parallel to the rails and of projecting ribs under the plates for lateral stability. The plates are held in position with tie bars, the connections being similar to that with pots; gibs and cotters, distance pieces and keys or keys alone being used. It provides the effective bearing area of 0.464 sq. m. per sleeper on Broad Gauge. Both, pot and plate sleepers, can be used with flat-footed and bull- headed rails, but they have to be casted accordingly. Jaws form an integral part of the casting in case of bull-headed rails.

42. CI PLATE SLEEPERS The various types of cast iron plate sleepers are being used such as DO plate sleeper (Denham and Olphert's sleeper). Laisly Pedestral , The lines patent, N.W.R. type, L.K. type, K.K. type, 3S/T.S. C.S.T. 4 C.S.T. 4A, C.S.T. 9, Rail free duplex sleeper.

43. C.S.T.-9 SLEEPERS This sleeper was standardized by Track Standard Committee . It has been extensively used on Indian Railways for the last thirty years and moreover, its comparatively satisfactory behavior has resulted in the withdrawal of all the previous designs. It has a triangular inverted pot on either side of the rail seat , a plate with the projecting rib and a box on the top of the plate . The various pieces are connected across the track by means of a rod. A rail seat or a chair is provided to hold the Flat-footed or Bull-Headed rail respectively with 1 in 20 cant . The C.S.T.-9 sleeper for B.G., weighs 103 kg and is heavier as compared to wooden sleeper. This can easily be assembled or dismantled without using mechanical equipment

44. C.S.T-9 SLEEPERS The tie bar is fastened to the plate by means of four standard cotters . Small variation in gauge can be corrected by these four cotters. The shape of cost iron support is such as to give a stable base for the rail , and high lateral and longitudinal stability to the track . The mild steel two way key resists creeping movement of the rail. The rail seat has 1 in 20 cant and is only 11.4 cm wide along the rails on B.G. This narrow bearing tends to reduce the rocking of the sleeper plate under the wave-action of the rail.

45. C.S.T-9 SLEEPERS The sleeper may be used in sections of track in corrosive conditions such as saline soil , industrial wastes in the atmosphere and for cinders and ashes dropped on the track in case of steam traction near ash-pits. Though the cast iron plate resists corrosion but the tiebar , cotter and key are susceptible to it . The bearing area is approximately equal to the effective bearing area of a wooden sleeper. The cantilever ends of the rails are long which lead to battering, and ultimately hogging of the rail end and deterioration of ballast under the joint which finally need the replacement of sleeper.

46. C.S.T-9 SLEEPERS Though CST-9 sleeprs are most popular so far on Indian Railways but they have certain limitations in their use on modern tracks with speeds higher than 120 km.p.h . (i.e. High and super high speed tracks). Therefore various improved versions of these sleepers viz. C.S.T.-10. C.S.T.-11, C.S.T-12, C.S.T.-13 and so on are being developed for use on modern tracks in light of their performance for high speeds suitability for maintenance using mechanized techniques, stability , etc.

47. C.S.T-9 SLEEPERS

48. C.S.T-9 SLEEPERS

49. RAIL FREE DUPLEX SLEEPERS A joint sleeper of cast iron known as rail free duplex sleeper has been used as rail joints in conjunction with C.S.T.-9 sleepers. These sleepers are used to prevent the cantilever action between the two supports of the sleepers at the joints. The size of each plate is 85 cm x 75 cm and the plate accommodates the ends of the adjoining rail. The rails are not held to the sleepers with any fitting . Duplex sleepers give added strength to the rail near the joint . Their use is not very popular due to the fact that rail ends supported on this sleeper get severely battered.

50. RAIL FREE DUPLEX SLEEPERS

51. STEEL SLEEPERS In India, thousands of kilometrage of track has been laid using steel sleepers. The design of steel sleepers should fulfil the following Requirements: The sleepers should maintain perfect gauge . It should be possible to fix the rails easily in the sleeper and without moving the sleeper longitudinally. The rail should have the sufficient bearing area on the sleeper. The sleepers should not be liable of being pushed easily out of position . The metal of sleepers should be strong enough as beams . They should be so designed that packing or tamping does not damage the edges They should be sufficiently heavy for stability .

52. SLEEPERS 5.3 Steel Sleepers Steel sleepers, being used in India, fulfil all required conditions except the last one. Therefore, the practice is to use wooden sleepers in track-circuited lengths. But insulation with the use of synthetic rubber sole plates is now possible. Steel sleeper is an inverted channel with folded ends . The folded edges which form a bulb, resist the damage caused by the packing of ballast . When placed on ballast, it takes a grip on the ballast and prevents its tendency of escaping out.

53. STEEL SLEEPERS Steel sleepers are casted in one piece . The fastenings to the sleepers are less in number and simple in nature. These have inverted channel section , so light in weight and can be easily handled. The gauge, by use of steel sleepers, can be easily adjusted and maintained . Manufacturing of sleepers can be done by a simple process. The life of sleepers is much more than that of wooden sleepers. Advantages

54. STEEL SLEEPERS In steel sleepers, generally, cracks develop at rail seat which need the use of saddle plate. The sleepers, being of metal, are liable to corrosion . The rounded ends of the sleepers do not prevent lateral shift . Steel sleepers like wooden sleepers do not act as insulators and hence interfere with track-circuiting and are not suitable for electrified tracks . The cost of steel sleepers is relatively more than wooden sleepers. Disadvantages

55. STEEL SLEEPERS

56. STEEL SLEEPERS

57. CLASSIFICATION OF SLEEPERS In all the above types, the cross-sectional area of sleepers is almost the same . The difference in the method of fixing the rails to sleepers , however, exits .

58. KEY TYPE IN LUG OR JAW SLEEPERS

59. LOOSE JAW SLEEPERS This is an improvement over the pressed jaw type sleeper . In loose jaw type, the holes are drilled or punched in the plate to accommodate loose jaws. At present, spring jaws are more common .

60. CLIP BOLT SLEEPERS

61. SADDLE TYPE SLEEPERS In these sleepers, the rail seat is strengthened by a saddle plate , which has two holes corresponding to the holes in the sleeper, on either side of the rail. The object is to strengthen the rail seat . In India , now-a-days, loose jaw-type and four-key sleepers are commonly used . To increase the life of steel sleepers and prevent them from corrosion action , they are dipped in hot coal tar before supply but such protection cannot be renewed on the underside of sleepers.

62. 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:

63. CONCRETE SLEEPERS

64. 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 of sub-soil salts. It is moulded easily to size and shape required by scientific investigation. to withstand the stresses produced by fast and heavy traffic.

65. CONCRETE SLEEPERS These sleepers are free from natural decay and attacks by vermin, insects . etc. They have maximum life when compared to other sleepers , the life under normal conditions is 40 to 60 years (as compared to 15-20 years for wooden sleepers). This is not affected by moisture, chemical action of ballast, cinder and sub-soil salt. There is no difficulty in the track-circuiting , required for electrifying the track. Advantages

66. CONCRETE SLEEPERS The high weight of sleepers helps in minimizing joint maintenance by providing longer welded lengths (i.e. use of LWR) , greater stability of the track and better resistance against temperature variation. The sleepers have higher elastic modulus and hence can withstand the stresses induced by fast and heavy traffic. Concrete sleepers in the elastic fastenings offers an ideal track in respect of gauge, cross-level and alignment. Advantages

67. CONCRETE SLEEPERS The weight of concrete sleeper is as high as 2.5 to 3 times of wooden sleeper, requiring the mechanical appliances for handling. They damage the bottom edge during the packing . The scrap value is almost nil . The damages to the concrete sleepers is very heavy in case of derailment . Disadvantages

68. DEFECTS IN SLEEPERS

69. RCC SLEEPERS These are of two types: Through type, Composite or Block and tie type. In the through type , when concrete sleeper is stressed, cracks on the tension side are inevitable. Though the cracks are very small and almost invisible but they tend to enlarge with repetition of the impact loadings of the fast trains. This is the main cause of the failure of these sleepers. These composite or block and tie type of sleepers are not subjected to same degree of tensile stress and have given excellent results in France where a steel tie of inverted T-section is used. It is not in use, at present.

70. RCC SLEEPERS

71. PRESTRESSED CONCRETE SLEEPERS All the disadvantages of reinforced concrete sleepers have been eliminated by prestressing technique for sleepers. In pre-stressed concrete sleepers, the concrete is put under a very high initial compression . The design is based on: The maximum permissible compressive strength of 211 kg/cm² . The minimum cube crushing strength of concrete in the sleeper is 422 kg/cm² at 28 days , and The pre-stressed wires are stressed to an initial stress of 8.82 kg/cm² .

72. PRESTRESSED CONCRETE SLEEPERS

73. PRESTRESSED CONCRETE SLEEPERS Disadvantages These are heavily damaged in case of derailments . The bed of the ballast is specially prepared . These are uneconomical . The standard of maintenance for the track, where these sleepers are used, is to be kept very high . They are more rigid in nature . The design and construction is complicated but even then the desired strength is not developed at the centre of sleepers .

74. SPACING & SLEEPER DENSITY The space between two adjacent sleepers determines the effective span of the rail over the sleepers . The spacing of sleepers, therefore, in a track depends on the axle load which the track is expected to carry and lateral thrust of locomotives to which it is subjected . The number of sleepers in a track is indicated by the number per rail length . Since sleeper also provides lateral stability to the track, so, more the number of sleepers more is the lateral stability. The number of sleepers, however, cannot be increased indefinitely as certain minimum space between sleepers is required for packing of ballast. In India, this minimum distance for manual packing of ballast is kept 30.5 cm to 35.5 cm except at joints

75. SPACING & SLEEPER DENSITY The number of sleepers per rail varies in India from M +4 to M+7 for main tracks, where M = length of rail in meteres (If N in place of M is used, then 'N' is length of rail in yards). In Britain, N+ 4 sleepers are used, while in America, M +9 to M + 11 sleepers are common in through tracks. This large number of sleepers in America is due to use of very heavy axle loads. Sleeper density: is the number of sleepers per rail length and it is specified as ( M+x or N+x ) , where M is the length of the rail in metres (N is the length of rail in yards) and x is a number

76. SPACING & SLEEPER DENSITY Varying according to the following factors and is fixed by the Railway Board for various axle loads. The factors governing the sleeper density are: Axle load and speed, Type and section of the rails, Type of ballast and ballast cushion, Type and strength of sleepers, i.e., Bearing area of a particular sleeper on the ballast. And Nature of foundation.

77. SPACING & SLEEPER DENSITY Thus, if M is the length of a rail in meters, the sleeper density is expressed as M. (M + 1), (M+2) and so on. For instance, if length of the rail is 13 m, 17 sleepers are expressed as M + 4 (i.e., 13 M + 4). This (M + 4) is the density of sleepers. The spacing between sleepers is not uniform. Three or four sleepers on either side of the joints are kept down close together. The joint sleepers are still more close to avoid loosening of ballast due to impact. In suspended joints, the space between the joint sleepers is 30 cm to 45 cm and that between shoulder and intermediate sleepers is kept 75 cm to 90 cm respectively or as per specifications.

78. SPACING & SLEEPER DENSITY If joints on curves are staggered, one additional sleepers is provided for each joint, to make each joint a suspended joint. Thus for sleeper density of (M+4) on straight length, the density on curves will be (M + 5). Depending upon Sleeper Density the spacing of sleepers is fixed. This sleeper density can also be expressed as number of sleeper per kilometer of track as for S.W.R. and L.W.R. (i.e. where rails are welded and length of rails has no reference) viz. 1540 sleepers per km. The sleeper density for S.W.R. and LW.R. and spacing requirements are given.

79. SPACING & SLEEPER DENSITY Sleeper Density (No. of sleepers per km) Centre to centre spacing between sleepers M.G. L.W.R Track S.W.R. Track 1660/km 60 cm -------- 1540/km 65 cm 66 cm 1310/km ------- 78 cm

80. SPACING & SLEEPER DENSITY Example : Find out the expression for sleeper density for a B.G. track if 19 sleepers are used under a rail length. Solution- Length of a rail for B.G. Track = 12.8 m 'or' say 13 m. Sleeper density = M +x Where, M=length of rail in metres . X = a factor depending upon several factors, axle load, Section of rails, etc. So, 19 = 13+x Hence, x = 6. So The expression for sleeper density, therefore, is M + 6 Ans

81. REFERENCES USED A Text book of Railway Engineering book by S.C. Saxena & S.P. Arora, Dhanpat Rai Publications- 8 th Edition 2021. Railway Engineering by S. Chandra & MM Agarwal, Oxford University Press 2 nd Edition, 2013 https://civiltoday.com/ https://theconstructor.org/ Images from google server and book’s illustrations.