QUOTE: Originally posted by emory Slugs aren't really engines--they are traction motor platforms--the controlling engine feeds electrical current to the slug to power its traction motors. Many RR's would use an old engine as a slug. They would remove the prime mover--the engine--and ballast the unit to compensate for the weight. My favorite slugs are the old F units converted by the KCS!! BTW congratulations Dougal for your TAMR position!