I've always liked The Train and Von Ryan's Express, both
set and shot in Europe. (The final scenes of Von Ryan's Express
were shot on a line near Innsbruck, Austria, which I've traveled a
numnber of times. When the movie was made, the line was not yet
electrified. Some scenes at the end which are supposedly right next
to each other were actually filmed several miles apart.)

Breakheart Pass also has some nice railroad action in it.

These three movies take only minimal liberties with the facts of
railroad operations, though they do stretch a few other points in
their plots. In all three of these movies, the railroad is a
central part of the plot -- and the directors appeared to make
an effort to get the railroad part as right as possible.

-- Ernest