RGS No. 42 is a C-17 class 2-8-0 "Consolidation" type steam locomotive built by the Baldwin Locomotive Works of Philadelphia, PA in 1887, originally as Denver & Rio Grande Western (D&RGW) No. 420.
It was sold to Robert W. Richardson in 1953 for the Narrow Gauge Motel in Alamosa, CO. The motel was later moved to Golden, CO and became the Colorado Railroad Museum, while the locomotive was later sold to Magic Mountain to fund the move of equipment to Golden. It was then sold in 1989 to the Durango & Silverton Narrow Gauge Railroad (D&SNG) in Durango, CO and has been placed on static display in their Durango roundhouse museum ever since.
It is currently stored in Durango, while D&SNG 486 is on temporary display awaiting a future overhaul and conversion to burn oil and D&SNG 478 is also on temporary display awaiting its future overhaul. D&SNG crews are unlikely to restore the locomotive back to operating condition anytime soon. However, RGS 42 is back on display in the D&SNG Roundhouse Museum as of October 11, 2023, since it was announced that K-28 No. 478 would be restored to operating condition and converted to burn oil starting in early 2024.