Greg,
I found the 452 was one of the first K-27's assigned to the RGS. As I went through the Dispatchers train sheets at the CRRM I found it in service on 12/15/1925. It showed up in December 1925, June 1926, January 1928. On January 20, 1928 it was assigned to a four engine freight extra along with 464, 454 and 348. The records at CRRM are not complete so I was not able to determine how long 452 might have been operating after the K-27's were initially assigned to the RGS.
On June 20, 1926 the following locomotives were assigned to trains on the RGS; D&RGW 452, 463, 464, 315, 316, 319, 201, 262, 303, 341; RGS 3, 12, 20, 22, 40, 41.
Scott