These files.
Railworks\Assets\DTM\DD40X\DD40XAssets.ap\Type01\RailVehicles\Simulation\DD40XEngineSimulation.bin
Railworks\Assets\DTM\DD40X\DD40XAssets.ap\Type01\RailVehicles\Simulation\DD40XEngineSimulation.out
I've found some strange stuff in mine, like "VacuumBrakeSinglePipe" being one. I noticed a lot of settings didn't seem to change, so I hacked away and still no changes or crashing for that matter.
That's why I'm wondering if something else is really controlling the simulation, or at least part of it...
I've changed every field that says 65 for maximum cylinder pressure or maximum pressure for maximum force to 60, but no change anywhere.
I've looked around a lot and came to the conclusion, that the Type01 folder must be the engines "default" folder for all versions. If I'm wrong, please correct me...

I never owned the original version either, just this new one.