Jon:
What is probably confusing is you have to remember the sequence of demolition that the D&RGW did to the Durango yard starting in 1968. The 481 and 497 are still sitting on the roundhouse tracks, but they demolished (in May of 1971) the last 3 stalls (8/9/10) of the roundhouse & boiler house where the engines are shown parked (photo taken in August of 1972). The turntable lines straight thru from the sand/ coaling tower track to the yard at the north end while the south end was severed by the new balloon loop...
Get your hands on "Grande Gold" by Andy Payne which has photos to help visualize the before and after of Durango yard when it was truely Mecca for the NG faithful...