Wash racks would only be at very large, modern facilities. The vast majority of steam engine facilities did not have dedicated wash racks.
A lot depends on what size facility you are modeling. Are you modeling a facility on a branch or are you modeling a major facility at a division point yard on a large class 1 railroad. They will have very different facilities. If you look at a N&W facility, they will be the "Cadillac" of steam engine facilities and will have stuff that other railroads did not.
I rather doubt that what is going on in Dr. Wayne's video is what is happening on a "Wash Rack". A "wash rack" is different that a "wash out" (ironically closer to Dr Wayne's picture than his video). A wash rack would be a concrete pad with steam hoses with long nozzles to steam wash the exterior of the engine and wash of grease and grime. A "wash out" requires dropping the fire, draining the water out of the boiler and takes many hours. They aren't going to do that on the turntable lead. On the wash rack, it would take 20-30 minutes to steam clean an engine.
Here is a picture of a wash rack:
https://www.shorpy.com/node/19622
A lot depends on what size facility you are modeling. Are you modeling a facility on a branch or are you modeling a major facility at a division point yard on a large class 1 railroad. They will have very different facilities. If you look at a N&W facility, they will be the "Cadillac" of steam engine facilities and will have stuff that other railroads did not.
I rather doubt that what is going on in Dr. Wayne's video is what is happening on a "Wash Rack". A "wash rack" is different that a "wash out" (ironically closer to Dr Wayne's picture than his video). A wash rack would be a concrete pad with steam hoses with long nozzles to steam wash the exterior of the engine and wash of grease and grime. A "wash out" requires dropping the fire, draining the water out of the boiler and takes many hours. They aren't going to do that on the turntable lead. On the wash rack, it would take 20-30 minutes to steam clean an engine.
Here is a picture of a wash rack:
https://www.shorpy.com/node/19622