Short Notes on Protection of Rail from Liner Biting

 Protection of rail from liner biting. 

Ans. Protection of rail from liner biting- 

Generally  in  yards  due  to  drainage  problem,  which  causes  dampness  conditions,   there  is  corrosion  mainly  in  the  rail  foot  area.  In  addition  in  stretches  where  passenger   trains run in the early morning hours, due to toilet droppings, there is reduction in the rail  foot  in  the  area  which  is  in  contact  with  the  liners.  The  remaining  section  of  the  rail  is   normally not affected in such cases. In case of rail corrosion at fastening location, the measurement of rail corrosion in  rail  foot  it  to  be  done  at  every  500mm  or  part  once  a  year.  The  format  for  this   measurement shall be as given below :- 

Rail corrosion at fastening location – 

1. To minimise the occurrence of this problem, as a preventive measure, at the time of initial provision as well at the time of periodic cleaning of central leg of elastic rail clips.

Graphite grease grade ‘O’ to IS:408 shall be applied on the underside of liners as well as moisture to the surface of the liner and rail foot, grease shall be applied along the boundary of liner to seal the liner boundary. In areas indentified to the prone to such corrosion. This treatment shall be done once a year and in other sections with concrete sleepers once in two years. 

2. In case of location identified to be prone to corrosion, shifting of rail from its position will result into stopping of further development of corrosion at same location and will result into increase in life. By shifting of rail from its posisition, the reduced foot section due to corrosion gets shifted away from the liner. Thus, its further reduction in foot thickness at same location due to corrosion gets eliminated and new location with normal thickness comes under the liner to accept further corrosion. Thus the reduction of foot thickness at one location gets stopped. This is to be done when the rail is relatively new and reduction in rail foot area is less i.e. reduction in rail foot is less then 1.5mm. This may be done by de-stressing. 

3. As this type of corrosion is observed more on gauge face side, changing/turning of rail will result into making the gauge face as non gauge face which will result into increase in life of rail as the reduction of foot thickness at same location will get stopped.