This crash was due to 2 signalmen breaking Rule 55. The 06:17 ex-Carlisle crashed into the Troop Special, which was carrying all the Royal Scots which only a seventh survived, and the 05:50 ex-Carlisle crashed into the remains of the Troop special. The 04:50 ex-Carlisle parked in the Up Loop and the Empty coal wagons special parked in the Down loop, causing the 06:17 ex-Carlisle on the Down Line to reverse onto the up line.
The accident occurred at 06:50 GMT. 226 people died, and 246 got injured.
For more information go here: https://en.wikipedia.org/wiki/Quintinshill_rail_disaster
This is a animation of what happened:
