Warner Bros. had an engine and a car or two on their ranch, just rusting away between uses. I used to work for the studios as a lighting technician. When "Roots 2" was shot the company used a private (Melody) ranh out in canyon country and laid the track as well as trucked in the cars, steam engine and a diesel. The train was done up differently on each side - one side dressed as an old timer with a steamer (non-working) out front and the other side as much more modern (40's) - after filming the old timer, they used a crane and turned the cars around, lost the steam engine and put the diesel (the steamer was dummied up with steam lines and a smoke generator - not working under steam) which did ALL the work on the front instead of pushing from the back. I got to ride it for the shots since I had control of the batteries for all the lighting on board. The Studios also used the Sierra a lot as well as the Ventura County system. There were a few locations in Arizona that had steam trains as well and the O.P.&E. up in Oregon got used for a few movies as well. The Durango & Silverton was also used quite a bit. The Fillmore and Western is now the closest working railroad and gets used a bit. Filmed up there on that thing with Charles Bronson as a secret service agent as well as some others.