Theres all kinds of ways to do what you're describing. Ben's created some nice little Ditch Crosser Bridges that work well if you can play with the terrain around it. After that were a little short on Prebuilt Concrete stuff like what I think Im seeing in that pic, but I've built stuff like it with some Russian content I found (Some of the russian bridges have insane Texturing done on them). One of the nifty things about bridges like that is that the ballast carries on straight over them, so you can just drop a normal track Spline over whatever you put down for the bridge structure. The hard part is getting the Terrain in close enough, high enough, to fill the area around/behind the abutments without using an abutment that is too overly large to begin with. One of the few real shortcomings of the Trainz Surveyor is that it does not do 3 Dimensional Z Axis subtlety very well, but you can get around this in most cases with some creative asset use.
Falcus