Overhaul time today versus "back in the day"

I think it is remarkable what the maintenance folks at steam powered railroads do today to maintain and keep in operation locomotives that were never intended to have lasted as long as they have.

I watch in awe as locomotives like the 493 are returned to operating condition. It takes time and more money that I'll probably make in my lifetime to do so.

It makes me wonder how long the process took back when steam was king and railroads like the Rio Grande had large, full-time, maintenance facilities such those found at Alamosa and Burnham in Denver. Facilities manned with complete staffs of skilled workers, spare parts usually on hand, and decent budgets.

How long would it take those crews to perform a complete rebuild of any of the K-Class locomotives? How long for a smaller locomotive like a C-16?

What is the average length of time today for shops like D&SNG who have to keep trains in operation while doing a major rebuild?