Question: I found a crowbar whilst dungeon 'splorin. But what mod is it a part of and what does it DO exactly?
RailCraft
A multi-purpose tool any rail engineer should carry. It makes removal of old rails a breeze and even works on http://railcraft.wikispaces.com/Detectors+%28Device%29 and http://railcraft.wikispaces.com/Item+Loaders+%28Device%29. Additionally, right-clicking on a rail will allow you to adjust the rail. Most of the time that means reversing the rail's direction, but some rails will open a GUI. Right-clicking a Detector Block, http://railcraft.wikispaces.com/Cart+Dispenser+%28Device%29, or Advanced Loader will turn the block to face the side clicked on.
http://railcraft.wikispaces.com/Crowbar+%28Tool%29
RailCraft is still active for anyone who still wants/thinks of using it - Just the default recipes are used for normal/booster/detector tracks.
I think it was Simpson that was using it before and wondered if the tweak would stop his work.