Thanks for your questions Both these issues are due to restriction with the lite version of RailClone. At present, it is not possible to collapse a RailClone Lite object to a mesh which is why you cannot add a UVW modifier or export it via FBX.
There are a couple of workarounds though. Instead of exporting via FBX, export using the Datasmith plugin. This uses a different technique and RailClone Lite exports absolutely fine. Of course, you still can't use the UVW modifier, but Unreal will generate some UVs for lightmapping for you automatically.
We are currently looking at removing this restriction in the Lite version, so hopefully this won't be an issue for very much longer.
All the best,