The Gualliguaica rail accident happened on March 11, 1971, near Vicuña, Chile, when a runaway train packed with children derailed next to a ravine killing twelve.
When the rail staff realised what was happening they unsuccessfully attempted to board the train in motion but being on a slope it quickly accelerated away from the station.
[1] President Salvador Allende was flown to the scene of the tragedy in an Air Force plane and demanded that those responsible for the accident be punished.
The enquiry into the accident observed that ideally all stations should be built such that no gradient exists on the lines passing through them; but the mountainous terrain in the area had made this impossible in the case of Vicuña.
It also stated that the brakes on the train were of the Westinghouse design so should be fail-safe although the locomotive had been running at idle at the time and a fault in the system may have gone unnoticed.