On this day in 1991, two diesel trains carrying commuters crash head-on, killing more than 40 people and injuring 400 near Shigaraki, Japan. This was the worst rail disaster in Japan since a November 1963 Yokohama crash killed 160 people.
Shigaraki, a town near Kyoto, is famous for its ceramics. On May 14, the World Ceramics Festival was being held in the town. Passengers filled a train in Kibukawa, which was to run along a 14.7-kilometer single-track rail line away from Shigaraki, at just after 10 in the morning. However, workers on the Shigaraki Kogen Railways (SKR) line could not get a green signal in order for the train to depart the station. The system showed that a train was approaching, but the workers, believing this to be incorrect, overrode the system and sent the train out, 11 minutes late.
Unfortunately, the system had been correct: there was another train on the line, a JR West commuter train carrying passengers toward Shigaraki for the festival. When a faulty-departure detector failed to work correctly, this other train was sent straight on a collision course with the SKR train.
The resulting crash derailed both trains and cost 42 people their lives. A subsequent investigation faulted the SKR workers for allowing the train to depart without a green signal, an action found to be dangerous and illegal. A signal engineer was also blamed for the defective wiring that led to the failure of the faulty-departure detector that should have prevented the collision. A 1999 civil trial resulted in a 500 million yen award to the victims against SKR and JR West jointly.