I was so impressed when I rented this DVD a few months ago, I looked on PBS's web store and ordered it. Its a very nice 48 min long show talking about Union Pacific's 3985 Challenger, how 3977 was saved from the welders torch, shows during 844's restoration. Its shows the back shop's, inside the seven stall roundhouse. It's in widescreen, and it's on sale on there webstore. I got it for $7.50.
http://www.shoppbs.org/product/index.jsp?productId=2268425&cp=&sr=1&f=PAD%2FFormat%2FDVD&kw=trains&origkw=Trains&parentPage=search