Aug. 8, 1963?
‘Great Train Robber’ Ronnie Biggs dies at 84 - The Washington Post
The Glasgow-London Royal mail train is seen at the Cheddington station. Biggs was part of a gang of at least 12 men who robbed the Glasgow-to-London Royal Mail Train in the early hours of Aug. 8, 1963, switching its signals and tricking the driver into stopping in the darkness. The robbery netted 125 sacks of bank notes worth 2.6 million pounds -- $7.3 million at the time, or more than $50 million today -- and became known as "the heist of the century."