When I built my version of the wood trestle I referred to earlier, it was curved and on an incline. Not that difficult to do as long as neither aspect is too extreme.
Similar to what Neptune suggested, I would do something like this:
-Photograph by Kevin Parson
The above example is actually a roadway bridge, but very similar to railroad bridges. I would not be surprised if it was a railroad bridge originally.
I would shorten the girder approaches and lengthen the center section to get the clearance you need beneath.
-Kevin
The truss bridge from Central Valley…
…is 21" long. I’d suggest that you buy two kits, then after determining the best place for a single support, alter the bridge kits to make each one’s length appropriate to span from both of the foam risers to the single support.
The support could be built as stone or concrete, or done as structural steel.
I used scratchbuilt moulds to cast the supports for the bridge shown above, and for the one in the foreground below (the bridges members are from Atlas and Micro Engineering)…
…while the taller one in the background, from Micro Engineering, used all M.E. kit materials.
This one used mostly M.E. supports (modified to accommodate the terrain) and girders atop each tower, while the deck trusses are from Atlas…
…much of it now hidden…
Wayne