I don't know about D&RGW, but I am aware, through my ATSF readings, that a 5000 could spend upto three weeks in the shops during a Class 5 lite or heavy overhaul. I'd expect that with three shifts running the ABQ Shops during WWII that the time was reduced, but I don't have any documentation--just passages in some of my books. I'd make an educated guess that the time taken also depended on the type of shop work needed, the availability of parts, the priority assigned to the locomotive, and the availability of the craftspeople needed to finish the job. Best of luck finding an answer.