No idea Since all I researched was how to build my layout and not modeling anything specific like road or time period, I just chose diesel. I remember they were more forgiving on less than excellent track work. Nothing fancy going on here like you guys have, just a little 4 x 8 for my son and I to play with. I'm sure I must have gathered a complete mix of old and new locos and rolling stock, and am on the verge of causing a temporal paradox that will end up destroying time and space as we know it. On the other hand, you've got to start out somewhere, right?