Wrong-side Failure - Accidents

Accidents

While accidents from the problem are rare, they do occur:

• 1876 - Abbots Ripton rail disaster - signals frozen by blizzard in 'clear' position (signal arm hidden in a slot in the post).

• 1938 - Charing Cross (Northern Line) tube crash - signal linesman rewires a faulty signal incorrectly, so that it shows green too soon; two Underground trains collide as a result, injuring twelve. Also Charing Cross (District Line) tube crash, signal linesman makes wiring error in cabin, two Underground trains collide, killing six.

• 1953 - Sydenham Rail Disaster - five killed

• 1976 - Glenbrook, New South Wales. Automatic signal in rear of a stationary EMU at "caution" when it should have been at "danger". Following goods train enters occupied signal section and collides with EMU; 1 passenger killed. Cause attributable to deteriorated wiring which allowed a false feed.

• 1979 - Invergowrie rail crash - signal was at "wrong" (i.e. indistinct indication) yet taken by driver to be a 'proceed' signal.

• 1988 - Clapham Junction rail crash - single stray wire causes false green signal and collision killing 35. The signals affected had been behaving strangely for some time, but not enough to pin down a real problem.

• 1980s - Valley Heights train collision - electrician wrongly replace out clear glass lenses with coloured glass causing false colour with reflected sunlight.

• 1980s - Southern Region of BR - driver of stationary train sees signal ahead go to green, while train ahead still on line. Track circuit wiring fault somewhat like Clapham Junction rail crash. Alerts signalman, no accident.

• 1990 - Cowan rail disaster, which occurred when sand on the rails insulated the wheels from the rails, causing a failure to shunt that allowed a trailing block signal to improperly display a clear aspect, resulting in a rear end collision.

• 2005 - Deelfontein rail crash - solder splatter bridges a relay contact. Most testing is done with the relays unplugged which would not detect the splatter, while the solder splatter is likely to lead to a difficult to trace phantom problem.

• 2009 - Ft Totten crash Washington DC Metro (WMATA). An inbound Red Line train stopped short of Ft. Totten station; the following train failed to stop and impacted at ~42 mph. Nine dead, 80 injured. Preliminary NTSB reports are that the AC track circuit transmitter was breaking into parasitic oscillation, and that coupled across the rack cabinet to the receiver.