On page 142 of Silver San Juan, First Edition by Mal Hope Ferrell, it says RGS 20, 22 and 25 saw occasional service on Cumbres and Marshall passes. One such use was during a 1922 shop strike, when the 20 and Silverton Northern "32" were used over Cumbres.
Are there more details about the RGS engines in service on the D&RGW? What about the SN loco, "32"? I'd assume the author meant 34, as there was no 32 on the SN. Were there other times SN locomotives were leased to the Rio Grande? Would love to hear folks who know more elaborate.