What is Rails? - Definition and Types of rails

What is Rails? 

Rails are steel girders placed an end to end to provide a level and continuous surface for the movement of trains.

What is Rail?

Types of Rails

  • Double Headed Rail
  • Bull Headed Rail
  • Flat-Footed Rail

Double Headed Rail  

Originally the rails used were double-headed made of I section or Dumbbell section as shown in the figure. The idea was that when the head of the rail is worn-out during the service period, the rail could be inverted and reused without increasing any extra expenditure. Such rails need to be supported on chairs that rest on sleepers. But later on, it was found that during the service the bottom table of the rail was dented by the long and continuous contact with the chair to such an extent that it was impossible to reuse it. This led to the development of bull-headed rail.

What is Rail?

Bull Headed Rail  

The bull-headed rail is almost similar to the double headrail. The only difference between the double-headed rail and Bull headrail is that in Bull-headed rail more metal is added to the head to allow greater wear and tear. The lower head or table was kept of just sufficient size to be able to withstand the stress be induced by the moving loads. The rail also required a chair for fixing it to the sleepers. This proved the greater drawback of this rail.

What is Rail?

Flat-Footed Rail 

To remove the above drawbacks, Charles Vignoles developed an inverted T shaped section known as flat-footed rail in 1936. Flat-footed rail is also known as Vignole rail. It has the following advantages over double-headed and bull-headed rails.
What is Rail?

Advantages of Flat-Footed Rails

  • For fixing flat-footed rails to sleepers, no chairs are needed. The foot of the rail may be spiked direct to the sleepers. This affects the economy to a great extent.
  • For the same weight, this rail is stronger vertically and laterally both than Bull-headed rails.
  • It is cheaper than Bull-headed rails.
  • It requires less fastening than Bull-headed rail.
  • F.F. rail gives better stability to the track as these rail distribute rolling stock load over a large number of sleepers.
  • F.F. rails develop fewer kinks and maintain a more regular top surface than B.H. rails.
  • F.F. rail gives longer life to the track and reduces maintenance cost.
                         The F.F. rails have been widely accepted throughout the world. About 90% track length of the entire world has been laid with F.F. rails. It has also been standardised on Indian Railways.

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Also, Read- 

1. Functions of Sleepers
2. Functions of Rails
3. Creep of Rail
4. Buckling and Hogging of Rails

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