As an aside I think I read that due to a manufacturing issue or miscalculation 2926 can only be run up to 280psi of boiler pressure instead of the original 300psi it ran with in service.
The issue was/is they purchased the incorrect thickness boiler tubes (some 'expert' led them astray, and they didn't bother to double-check with crews of SP4449 nor the UP Steam Crew manager in Cheyenne, many years ago). Thus, they are only "allowed" to operate at 290psi maximum working boiler pressure.
Is that correct? I'm curious how much that will have an effect on its performance.
It will not have any effect on performance for what they will be doing.