Four trains were involved, a signalman was leaving his shift and forgot to inform the replacement that there was a train waiting at the junction. Two trains eventually crashed into the train that was waiting and a 4th train that was waiting in a nearby railway layby was also hit by derailed train parts. It's like something out of Thomas the tank engine.
The incident happened at Quintin'shill near Carlisle in 1915.
Source : Amazing and Extraordinary Railway Facts by Julian Holland, ISBN 978-0-7153-25827-7
