Having did my EE co-op work in a coal fired power plant, I think I can date the thing.
My plant started in 1917 or about, units 1&2. Those got ripped out to make space for unit 8 turbine which went online in 79-80. Units 5, 6, 7, and 8 where operating when I was there. Units 3&4 had been mothballed. It would cost to much to remove all of the asbestos. As long as it is wrapped tight, it is was safe.
To answer someone else, yes you saw a turbine and generator, but they were striped of the outer covers and asbestos removed, and now rusting.
One of the prints also gave away some clues, It showed a generator with a rating of 30,000K watts. Small stuff, but state of the art back then.
Based on the style of equipment and size rating of the unit, I would have to say it went online in the 1930s.
The control room was like some said, 60 vintage, but it was added later in the unit's life. In the 30s they didn't have control rooms, more like a central area with a lot of manual hand wheels that had long shafts on them that controlled air dampers to the boiler.
I can't understand why a utility would run a unit that long. The efficiency had to have sucked. Just the temps and pressures they ran the units at dictate the best you can do, second law of thermodynamics. From the early 60s on, 2400 PSI and 1000F steam was the standard, I bet that old unit was at 1800PSI and no superheat on the steam.
Maybe it was a dual use plant. it could have made lower pressure steam for heating of a nearby complex, or for some process, like a paper mill.
Fond memories of the plant. Even a modern one can be a rough and dangerous place. So much stuff could kill you before you have time to react. A steam leak for example. You don't see superheated steam, it is a gas, you see it some distance away as it condenses to water vapor. You just stayed aware of things and went about your job.