Schlafwagen nach Triest
Sleeping Car To Trieste (original)
Starring Jean Kent, Albert Lieven, Derrick De Marney, Paul Dupuis, Rona Anderson, David Tomlinson, Bonar Colleano, Finlay Currie, Grégoire Aslan, Alan Wheatley
It's a thriller movie, and has a rating of 6.6 out of 10 from Imdb which is usually fine for this kind of movie.
Watch it here
Not found streaming from Belgium.