Please please PLEASE add the Union Pacific 4014 'Big Boy'! It would fit very well in the union pacific routes. It is such an iconic locomotive.
DTG are no longer doing steam traction for TSW. Also, the current state of Simugraph can barely cope with the relatively simple steam physics of the UK locos in the game. A complex machine like the Big Boy stands no chance, sadly.
as of now a Third party developer named Train Sim Germany is currently working on a German based Steam Loco route and he's currently trying to improve the steam loco simulation physics in Simugraph. Hopefully whatever improvements he did can be applied to future and current steam loco dlc's in TSW.
Oh yes I know that, but TSG projects can take months or years even before coming to fruition and we haven’t seen any proof of concept yet they have the BR52 working in good order. Of course, if they pull it off I would be delighted to see someone like Smokebox have a go at some US steam; I just don’t think we should get our hopes up too much.