I was a B-52 and KC-135 flight simulator tech stationed at Fairchild AFB from 18 May 1980 - September 1990. I worked on these very railcars until the sim positions went civilian contract (September 1990)

We were told they were repurposed 1918 Pullman railcars. The sim cars were originally build to be on the move so they were self contained with their individual, independent generator, aqua zone heaters / air conditioners, bathrooms, kitchen stove, drinking fountain, and bunk beds. Of course by the time I arrived on station they were permanently parked on rails between The Communications Squadron in the building (old WWII warehouse) to the north, and the Four seasons store & Class 6 store to the south. These two warehouse buildings were between O'Malley Rd and Olympia Avenue with the rail line (and sim cars) sandwiched between them in the alley way.

They were only moved one time in my 10 year stint at Fairchild. The B-52 sim cars were towed to Hill AFB (Tooele Army Depot in the NW corner of Hill AFB) to have their wheel bearings repacked; Cars painted ETC.

Their exact position / location was with the B-52 railcar with the expandable sides containing the cockpit was the first car in the line. It butted up to the road (Arnold St.) and faced the flight line. The expandable sides were on the end opposite the street. It went B-52 electronics car, then B-52 office car, then KC-135 Electronics car, then KC-135 office car. They were all connected in a four car string.

We decommissioned both sims while I was there. It was my understanding that the B-52 would become a simulator mockup for the museum while the KC-135 would be gutted to become an art gallery. This activity would have taken place after I departed so I cannot verify if that actually happened! I would be happy to answer any questions you may have.