>>8953242The US started dropping steam in favor of diesels in earnest in the 1950's. Norfolk and Western and Union Pacific were some of the last Cass I holdouts and retired the last of their steam around 1958. The saving grace for preservation is that lot of Class II and Class III roads held onto steam well into the late 60's since the initial outlay for diesels was high compared to keeping the steam they had running. A lot of locks got scrapped. Then there was a revival of interest in steam in the 1970's and there was a scramble to preserve what was left.
