They are still too outside my era. 1956 is approaching the 60's. I cutoff at 1953- however I think the cars are so cool I can forget about my era!
I've been having the same problem. For the Santa Fe in 1956, it brings about a lot of modifications. However, running the El Cap/Super Chief would be spectacular.
Perhaps Scott can come up with something else to appease me in the not to distant future. I sure would like a streamlined 1949 Chief with the NYC, Pennsy, and B&O transcon cars.