Some great photos, I only wish the 4500 and her two remaining sisters--heck, every steamer in the country--could be restored to operation.

The last photo, in which the engine is being pushed across the highway, shows this spur coming off a railroad that looks like a former interurban, what with that side-of-the road alignment and that power line. Indeed, the railroad's name--Tulsa-Supulpa Union Railroad--even sounds like a former interurban. Was this so?

Yes, that railroad started out as an electric interurban lline. Here's a short history from their website.

http://www.tsurailway.com/history.asp

The groups that put in all those hours on the engine and cars did a great job.
My main interest is in the Murray Hill which was a Pullman Bedroom Lg car that ran on the NH/PRR Federal Express between Boston and Washington DC. My Dad was a Pullman Conductor working out of GCT and he has told me about working the Federal a few times even though it wasnt a GCT train.
After Pullman had that anti-trust suit it went to the NH who leased it back to Pullman. There werent many routes the car could operate on as it had beds in it instead of berths that folded out of the wall.
The group here in Tulsa who fixed up the car took a bit of Poetic License by putting quotes on the car name, gave the wrong info as to the correct type of car, TSU and NH called it a Business Car after it was removed from Pullman Service and they have painted Pullman on the car end.

It is my understanding that the car was indeed used as a business type car late in it's life. That is why it survived.
T7