Right then, I watched this at university on a slow Sunday. I seem to recall I was drunk which did nothing to improve my memory. The film is one from the rich vein of 70's disaster movies and I remember precious little other than it centred around a train that had been hijacked or otherwise turned over and wound up with it speeding toward some kind of precipitous doom with a police officer and one of the villians sat apathetically in the heavily damaged cab. This scene had no real dialogue and not much music either. There was a great deal of snow and the train was a very dark grey, almost military in nature. Similar to the Cassandra crossing but bleaker if you know what I mean. Not much to go on but any ideas?