I agree that a steam railroad might not just go out and rent a diesel. Even by 1956, diesel locomotives were still somewhat cantankerous. Unlike steam, where a knowledgable machinist and welder could keep it going, diesel-electrics require specific skills of a diesel mechanic and locomotive electrician.

> .... however if they wanted to lease power from SP, it didn't necessarily have to be steam, they could have leased diesel power just as easy.

True, SP did have switchers assigned to Ashland, Medford and K-Falls. But were any of them "extra" and available for lease? In that era, railroads were still buying and assigning switch engines specifically to certain yard jobs on a one-for-one basis to replace steam. (For example, the first order of GE 70 tons were used to retire the 4-8-0s in Oregon.)

I think a big consideration would have been cost. What would be the rental rate for a fully paid for steam locomotive that may have not been needed at the moment, compared to a fairly new diesel bought for a specific assignment? Did McCloud have surplus power in 1956? or did the SP?