Short Note on Distressing of LWR

Distressing of LWR

When is distressing Necessary:- Whenever there is abnormal behaviour of LWR as indicated below, distressing should be done:

i. Gaps at SEJ : whenever the gap observed at SEJ differs beyond limits specified or exceeds the maximum designed gap of SEJ or when stock/tongue rail crosses the mean position.

ii. After special maintenance operation: After special maintenance operations viz. Deep screening, lifting or lowering of track major realignment of cures sleeper renewals other the casual renewals and rehatibiliation of bridges and formation causing disturbance to track.

iii. Unusual occurrences: after unusual occurances viz rail fractures or replacement of defective rail/glued joint, damage to SEJ/ Buffer rails, bucking & breaches etc. iv. Temporary repairs: if number of locations where temporary repairs have been done exceed three per km. 

Procedure for Destressing without use of rail tensors.

(i) A traffic block of adequate duration say about 3 hours is taken at such a time when the rail temperature is between tm+5 and tm+10c, for 60kg/52kg rail or tm- to- tm+ 5c for lighter rail sections, Before the block is taken a speed restriction of 30 kmph is imposed and fastenings on alternate sleepers loosened.

(ii) During the block the closure rail are disconnected and the S.E.Js are adjusted to be in the mean position.

(iii) The sleeper fastenings on both the rails are loosened, starting from the S.E.Js to the centre of LWR iv. The rails are lifted and placed on the rollers at about every 15th sleeper, to permit free expansion the rails are also struck with wooden hammers to help in distressing.

iv. The rollers are then removed and the fastenings tightened, starting from the centre of LWR towards SEJ the tightening of the fastenings must be completed in the defined temperature range of destressings.

v. A cut rail is provided between the S.E.J and LWR keeping adequate provision for thermit welding.

vi. Thermit welding of joints is done subsequently to complete all the operations of distressing. Destressing of the rails should be done simultaneously. While distressing on curves the rails should be provided with the lateral supports at an interval of 10 sleeper on the inside of curves and at an interval of 30 sleeper on the outside of curve. At time of distressing, a gap of 7 to 8 mm should be provided at each of the fish plated joints of the buffer rail assembly.