A "Slug" is a type of railroad Stock with no Prime Mover but Traction motors they get power via a "Mother" (regular loco) commonly used in yards. This Suggestion is for Sand Patch Grade Yard Slugs: A Yard Slug is like a B unit but with out A Prime Mover and as Previously Mentioned Siphons power from its mother and Proves useful on Low power operations where if to much power were to be Applied the loco normally will get wheel slip, with a slug said power would also go to the slug and the load Balances. These could be used on Switching Services, although they might be slightly boring for TSW2 Road Slugs: A Road Slug looks like a regular loco but said Loco has had there worn out Prime Mover removed and is just converted to Slugs but still retains its cab and act as a Cabcar, they work in "Sets" of sorts, CSX Road Slugs were Converted from GP30/35/and 40s, these were Paired with Specially wired GP40-2s which could make a Opportunity to bring the GP40-2 Back. These would be a Better choice of Slug. I made this because Slugs would add a interesting piece of Railroad stock to TSW2 that we haven't really seen in TSW2 or TSC before yes it may be slightly boring but I still think slugs would still be interesting thing for TSW2.