So many of you know at this point of the C&O 1309 so yeah its going to be the biggest compound locomotive to run, want this in TS? link: Chesapeake and Ohio 1309 - Wikipedia
Well. There's always the most viewed suggestion on all the forums, The New River Gorge-huntington To Hinton West Virginia (csx/c&o New River Subdivision), that would give a C&O H6 a home route to run on.