I can not place bulk rail loaders and unloaders down over roads from the transport drone mod. However, once they are placed down, I can add the roads back in and they get placed "underneath" the brl and bru. I have had a poke about with the prototype visualising tool, and the reason seems to be the bulk rail loader and unloader pump prototype which has within its collision mask "layer-17" which is the layer identifying roads. I don't think this is set for any of the other composite entities that make up the loaders and unloaders.
I am not sure the best way to resolve this. We could encourage transport drones to not add its road layer to the mask, or we could manually strip it out, or perhaps there is some third option. I am happy to add any fix to my Transport Drones on Asphalt mod, as it's where I'm putting various compatibility fixes, but I'm not sure exactly what the correct fix would be in this case.
