i think what you meant is that the northeast had many cool engines. The NYC Niagras are long gone, unlike the Big Boys and Challengers. The New York Central ran as far west as Indiana and Illinois, i don't think this is a stretch, particularly if your railroad is not set in a certain time period.
Personally I don't have a set time period for my layout, since it is a fictional place I can imagine that is a junction for a variety of railroads that come through town or have trackage rights, or that some steam locomotives were preserved and brought there that hadn't survived in real life. Although I would like to set a future layout in the transition era, I might still have a separate area where anything goes. A lot of fun stuff out there. I have a lot of respect for any modeler though, that can be dedicated to a specific time period and place.
