Top 10 Films Set on Trains. Horror Express (1973)
The Taking of Pelham One Two Three (1974)
Von Ryan's Express (1965)
Breakheart Pass (1975)
The First Great Train Robbery (1979)
Unstoppable (2010)
Under Siege 2: Dark Territory (1995)
The Flying Scot (1957)*
The Polar Express (2004)
The Great St Trinian's Train Robbery (1966)
Special mention to
The Ghost Train (1941) which would have made my top ten (God knows why) but it's set in a station rather than on a train following the first few minutes.
There are so many films which have scenes on trains that are memorable (
Mission Impossible, From Russia With Love, to name two) but i've gone with films that are mainly set on trains.