Derailment is a kind of accident that occurs when the wheels
of a vehicle mount the rail head. It causes excessive damage to the track in
general and sleepers in particular.
The following actions should be
taken in the eventuality of a derailment on a track with concrete sleepers.
(a) When the
damage to concrete sleepers is not extensive and it is possible to allow the
traffic to pass at a restricted speed, suitable speed restriction should be
imposed after assessing the damage to the track. Sleepers should be replaced as
in the case of casual renewals while taking all precautions. After all the
damaged sleepers are replaced, the affected portion as well as the portions 100
m on either side adjacent to it should be distressed, and normal speed should
be restored after consolidation.
(b) When the
damage to the concrete sleeper is extensive and the track is distorted in such
a way that it is not possible to allow traffic to pass even at a restricted
speed, the affected portion should be isolated by introducing buffer rails on
either end of it. The distorted track should be removed and replaced by the
track laid on single-rail panels using the available rails and sleepers. The section
should then be converted into long welded rails using concrete sleepers, taking
the usual precautions laid down in the LWR manual.