Hey George, I had no idea you were modeling so modern an era with the Rock. Kewl.
Scoob, I'm modeling 1980 so same story, diesels all the way. However, you gotta love the steam engines, so I do have a steam locomotive passenger excursion. Currently lead by a Mehano 4-4-0 American (UP), but I've wishlisted a Rivarossi 4-6-2 Heavy Pacific (ATSF) at Walthers. Only $130US - mom, dad, Heather - you guys listening ????
I love seeing people who model the transition era, too, that includes both in almost equal numbers. One freight train might be lead by a steam, another by a first gen diesel. If I wasn't modeling 1980, that would be my second choice era.
Course, steam locos usually cost more than diesels too. Well, I'm babbling, time to go.