Hi, we have been checking this problem and is a limitation of V-Ray. On Chaos Group forum
Vlado writes:"It will not work on proxies for now; this is because when used as a bump map, VRayEdgesTex needs information for the entire mesh - obviously this is not possible with a proxy."
RailClone uses the instancing engine used by V-Ray proxies, so these limitations are shared as well.
The workaround is turn off Display->Use Instancing engine
. But doing this, RailClone will generate an unique mesh with the geometry, which may be huge depending of the model. So, be care with it.