Information about Rails

                                            Rails

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

•The two rails of the track also serve as a lateral guide for the running of the wheels.

Function of Rails:

1.Provide smooth surface with lesser  friction                     2.Provide continuous and leveled  surface

3.Provide lateral guidance to wheels

4.Bear stresses developed due to vertical   loads, thermal  and braking effects

5.Transmit loads to greater area below

Classification Of Rails:

Rails can be classified into the following categories:

1.Double headed rail

2.Bull headed rail

3.Flat footed rail

Double Headed Rail:

•It is of I section or Dumb-bell section.

•Such rails have to be supported in chairs which rest on 

sleepers.

•The idea was that when the head of the rail was worn

 out during the period of service, the rail could be 

 inverted

•Later 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. Hence it was rejected and other

 types of rail were searched.

Bull Headed Rail:

                                                                   •It is similar in shape to double headed rail with only difference that in bull headed rail more metal is added to the head to allow the greater wear and tear.

•The lower head or table was kept of just sufficient size be

able to withstand the stresses to be induced by moving loads.

•This rail also required chairs for fixing it to the sleeper.

Flat Footed Rail:

                                                                   •It is in inverted T-shaped rail i.e., the foot is spread out to form a base

•Having greater stability

•It was developed by Charles Vignoles in 1836 A.D

•This form of rail became so much popular that about 90% of railway tracks in the world are laid with this form of rails

Advantages of flat Footed Rails:

                                                                      •They don’t need any chair and can be directly spiked into the sleepers which affects economy to great extent

•Requires less fastenings

•Give  better stability to the track

•Give longer life to the track and reduced maintenance cost

Wear Of Rails:

                                         •During the service life of the rail, due to passage of number of wheels, the friction between wheel and rail, forces caused due to acceleration and deceleration and the effect due to weather condition like temperature, snow and rains and the standard of maintenance of track, considerable wear and tear is caused on the vertical and lateral planes of a rail head