Hey all, had a question pertaining to bridges. When a railroad is running through a canyon with a small stream, and it has to cross it quite a few times, do they (railroad) like to keep those bridges the same kind, or is it possible to see a wide variety of different kinds, i.e. a deck girder, a thru truss, and, say, a small wood trestle? Thanks -Mike
I would think there would be some variety. It all depended on how long the span happened to be and other variables such as the type of footing, rock or gravel etc. as to the type chosen. Then there were things like replacing them after they were damaged by a flash flood or rock slide. A newer more modern bridge could be a replacement or they might drag in an old one salvaged from somewhere else.
They would use the cheapest for each situation, but for what you describe each 'situation' would probably be much the same - same stream, probably similar span, etc. - so they would likely end up with the same thing. For a model you can use licence to vary things a bit. For short crossings near a right angle to the stream use a plate girder, for longer crossings at a steeper angle use a truss. Deck or through depends on clearance below. If the rails are near the water level the bridge would likely be a through type, but if say 10ft above probably a deck (depends a bit on expected flood levels). However, a truss is deeper, so you might have a deck plate in one location with a through truss at the next, more angled, crossing.
Russ and Mike, thanks. That helps clear things up. I was hoping to have a little variety in my canyon scene, but wanted to know what the big boys did first. Thanks again -Mike
