I switched era's in late 2012 or early to SP&S from Burlington Northern, it's interesting restarting but in the end I don't regret swapping. it helped me restart and get DCC swapped. Plus there's more color in the cars and locomotives.
I'm glad to be back, I got a new job, had moved, and crashed my bike. SHe's all fixed but my wrist still hurts from time to time. I'm happy to be back in the hobby!
So, I think I'm going to go with the change when the move is done and I get settled, it will be a 1955'ish time frame on the ATSF. That seems to give the best options for motive power, freight, and passenger equipment around that time. I'm not one of those modelers that will only run it if it fits that exact year but settling on a year helps me not jump to far either way when picking up new items. With that said, my first big step toward this change was placing a pre order with a Trainboard advertiser for the upcoming (and appropriate for the time period per the September UMTRR) M/T 40ft ATSF Impact Car. Thinking my first projects will be repaints of some older Atlas locos I have (GP9's and RS3's) along with maybe a MOW or wreck train. Have an old Model Power crane that would probably look good done up in the old black and silver ATSF paint scheme.