There are different ways to build this bridge. If you want to make it parametric (so, i.e. the distance between pillars can be changed), use several linear generators:
1) Structure: Start/End segments for the end pieces, Default segment in scale mode for the arc and Evenly for pillars.
1) Road. Just a simple linear generator with a Default segment (there are several samples in the Library).
2) Railing. See the library for examples.
Anyway, this case may be a bit hard to start with RailClone.
If you have not used the software before, i suggest you complete our tutorials
before (starting by the Mansory Wall
). It will help you to understand better the RailClone basic concepts.