The Narrow Gauge News of Dec. 1952 reported that 486 and 487 were removed from Salida to Alamosa in late 1952. I suspect 487 had been out of service in Salida for some time, as I have seen no in-service photos of it in Salida after 1951.
NG News research indicates that 485 was not initially in Salida after Valley Line abandonment, but was there by July 1952 (possibly to replace a possibly ailing 487?). NG News also reported the K-36--K-37 trade between Salida and Alamosa began in early 1950. Thank you, Bob Richardson!