Car Maintenance

Hi Guys,
I posted this awhile back and got no responce so I thought I would try again. I have several questions about the Rio Grande's car maintenance program in the 40's. How many car shops were there and where were they? Were cars cycled through the shops on a timed basis such as every three years or only when they were in need of repairs? Were cars always painted when they visited the shops or only if they needed it? Were cars sent to the shop just to be repainted? Does anyone have an idea how many cars would be in the shop at one time on average and what would be the average stay? I'm trying to get a feel for how often the freight equipment was painted.
I'm also curious how a bad order car made it to the shop? I've heard lots of stories about a car being set out on a siding for one reason or another, so I wonder, if the car couldn't be moved in the train it was all ready in how did it get to the shop? Some kind of a special train? Was it common practice to work on cars where ever they were set out? If it was a loaded car they must of made arrangements to get the load transfered to a working car.
Thanks in advance.
Bill W