Rail fastenings and joints

railway engineering

1. TRACK FITTINGS AND FASTENINGS 1 Prepared by L. Devendiran .,DCE.,BE.,

2. Rail joints 2

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4. FASTENING SYSTEM 4 Rail fastening system is a means of fixing rails to sleepers Used to keep rails in proper position Important fittings are: FISH PLATES SPIKES BOLTS CHAIRS BLOCKS KEYS PLATES

5. FISH PLATES 5 Fishplate, splice bar or joint bar is a metal bar that is bolted to the ends of two rails to join them together in a track Maintain the continuity of rails & to allow for expansion and contraction of rail due to temperature difference. Maintain correct alignment of line both horizontally & vertically. Fishplate is a small copper or nickel silver plate that slips onto both rails

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7. 7 FISH BOLTS BONE SHAPED FISH PLATE

8. REQUIREMENTS OF FISH PLATES 8 They must support the rail and top of the foot They should allow free movement of rails for expansion & contraction , They should bear stresses due to lateral & vertical bending moments They should hold ends of rail both laterally in line and vertically in level They should not wear due to impact, expansion & contraction Length of fish plate should not exceed 457mm in India.

9. FISH BOLTS 9 Holes are drilled through plates and web of rails and then fish bolts and nuts are provided in these holes. Alternate holes are made elongated and oval shaped so that bolts in the rails will not be turned by vibrations. Holes are made of larger diameter generally 5mm- 6mm to allow for expansion & contraction.

10. 10 Bone shaped Fish plate Rail Hole for Fish bolt

11. SPIKES 11 To hold rails to wooden sleepers. A rail spike is a large nail with an offset head that is used to secure rails and base plates to sleepers

12. REQUIREMENTS 12 The spike should be Strong enough to hold rail in position & enough resistance to motion to retain its position Cheap in cost Deep as possible for better holding power Easy in fixing and removal from sleepers Capable of maintaining the gauge

13. DOG SPIKES 13 Commonly used Hold rail flanges with timber sleepers Shape of head of spike resembles ear of dog ,hence called dog Spike Section of spike is square – shape & bottom part is either pointed or chisel shaped Cheapest, easy in fixing and removing from sleepers Maintain better gauges

14. DOG SPIKES 14

15. SCREW SPIKES 15 Tapered screws with V- threads used to fasten rails with timber sleepers. Head is circular with square projection

16. SCREW SPIKES 16 Holding power is double that of dog- spike Resist lateral thrust in better way More costly Gauge maintenance is more difficult Driving operations are similar to dog -spikes

17. ROUND SPIKES 17 Head either cylindrical or hemispherical Used for fixing chairs of bull headed rails to wooden sleepers Limited use only

18. ELASTIC SPIKES 18 To overcome the problems of dog- spikes head absorbs the wave motion of rail without getting it loose. Provide better grip and result in reduction of wear and tear of rail Commonly used in British railways

19. BOLTS 19 1. FANG-BOLT Alternative to round spikes Not in much use due to difficulty in fixing and removing bolt 19mm in dia and of sufficient length to pass through sleeper

20. BOLTS 20 2. FISH BOLT Made of medium carbon steel Length of bolt depends on type of fish plate used Too much tightening is prohibited as it prevents free expansion & contraction of rails

21. CHAIRS AND KEYS 21 For double headed & bull headed rails chairs are used to support them in position Made up of cast iron Distribute load from rails to sleepers Chairs have been fixed to the sleeper using wooden spikes screws, fang-bolts or spikes Chair consist of 2 jaws & a rail seat Web of rail is held in inner jaw of chair and a key is driven between rail and jaw of chair

22. Chairs and keys 22

23. 23 KEY RAIL CHAIR

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25. CHAIRS AND KEYS 25 Chairs are fixed to sleepers using 3 spikes Keys may be of wood or metal and may be either straight or tapered Wooden keys are cheap Initial cost of steel keys is high. But life is about ten times more than wooden keys. So steel keys are preferred

26. BEARING PLATES 26 Rectangular plates of Mild steel or cast iron Used below flat footed rails to distribute the load on a larger area of timber sleepers Placed below rails carrying heavy vehicles at high speed

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28. BEARING PLATES 28 Advantages:- Distribute load to sleepers over a large area and prevent sinking of rail in soft wooden sleepers Prevent destruction of sleepers due to rubbing action of rail, increase life of sleeper Help in firm and perfect holding of spikes to sleepers which prevent shifting of rails Better maintenance of gauge

29. BEARING PLATES 29 Disadvantages:- Plates rattle when loose When any hole for a spike is failed and a new hole is to be made , all spikes in the bearing plate have to be pulled out which affects good hold of spikes. When bearing plates are loose , they admit moisture and result in mechanical wear of sleepers

30. Plate laying 30

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32. Telescopic method 32 In this method the plate laying is done by manual labour. This method is widely used in india . The stages are, Material gangs Linking in gangs Packing in gangs

33. Plasser quick relaying system 33 Plasser and theurer cmpy has introduced mechanical relaying system. Relaying with pqrs The track is dismantled at site, panel by panel laid in wagons with the help of portal frames.

34. 34 Thank you…