Hostler-thanks for reviving this topic! Yes, we had a good thread going on the old site, I'm glad to see there's still interest.
Tough Guys-IIRC there was an article on the filming of this movie in an issue of "Railfan", you're right, they used both a large scale model and a full-size mockup of 4449 for the wreck scene.
My favorite railroad movies? Probably the same ones I'd listed before:
The Titfield Thunderbolt-filmed in 1953, about a group of British townspeople who start running their local branchline when it is threatened with closure. Great color (or colour, if you prefer) shots of British steam.
The Molly Macguires-not a railroad film per se, but lots of railroad scenes using 4 foot gauge equipment from the long closed Carroll Park and Western, lettered "Carbon and Schuykill" to represent late 1800's anthracite railroading. (A subsequent poster informed me that the steamer used in this movie is now at the Pine Creek Railroad in New Jersey.)
Buster Keaton's silent classic "The General". Filmed in 1927 on a logging railroad in Oregon, this one includes some great shots of some truly vintage equipment. In this one, they REALLY DO wreck a locomotive when it crashes through a burning trestle!