Railway Accidents

Track maintenance
Track needs regular maintenance to remain in good order, especially when high-speed trains are involved. Inadequate maintenance may lead to a "slow order" (North American terminology, a "slack" or speed restriction in the United Kingdom) being imposed to avoid accidents. Track maintenance was at one time hard manual labour, requiring teams of labourers (US: gandy dancers, UK: platelayers or trackmen, Australia: fettlers), who used lining bars to correct iregularities in horizontal alignment (line)of the track, and tamping and jacks to correct vertical irregularities (surface). Currently, maintenance is facilitated by a variety of specialised machines.
The surface of the head of each of the two rails can be maintained by using a railgrinder.
Common maintenance jobs include changing crossties (sleepers), lubricating and adjusting switches, tightening loose track components, and surfacing and lining track to keep straight sections straight and curves within maintenance limits.