Here's the crash log - I tried to work out what was happening, but I couldn't even find the package called compatmod in the source. Using latest versions of Forge, Reborn Core, Tech Reborn and RailCraft.

EDIT: just saw that the package is instead part of 'TechReborn-ModCompatibility'. What I imagine is happening is that part of RailcraftFluids.CREOSOTE.getBlock().getFluid() is crashing, as we disabled RC creosote in the configs.