Greg, I once did a Super 8 of a Santa Fe line I ran on between Abilene, KS and Superior, NE. There are a fair number of views from the cab. The engines were mostly SD40-2s i.e. EMD (EMD=Engine May Deafen) "screamers" and the track was welded rail. When I ran the movies all that could be heard was flange squeal and general noise so I taped sound from a trip on the KYLE on jointed rail with a GE U-30C with it's distinctive exhaust. Not right for the purist but it sure makes a better movie.
It doesn't matter now as the sound is out on my Minolta projector. JP