Great Work!
I also found this: Denver Public Library, Western History Department, lists these on file in the Oversize Equipment Drawings, Series 2, Denver and Rio Grande Western Railroad Company Records, WH512.
Lettering, Narrow Gauge, Switch Engines (Card: 2755 File: L-357 ), October 2, 1906
Lettering, narrow gauge engines (Card: 7127 File: L-557 ), November 14, 1921
Item — Tube: 24
Lettering and Painting, Narrow Gauge and standard gauge engines (Card: 5417 File: L-457), undated
Item — Tube: 7
Classification Lettering, all engines (Card: 5044 File: L-157), undated
Item — OVBox: 11, Folder: 8
Dates: undated
Lettering (Card: 7105 File: C-573 ), August 26, 1921
Item — OVFF: 135H
Lettering (Card: 7095 File: C-573 ), October 13, 1921
Item — OVFF: 135H
Lettering (Card: 10668 File: C-573 ), October 14, 1925
Item — OVFF: 135H
Lettering, Narrow Gauge (Card: 16554 File: C-573), January 1937
Item — OVFF: 135G
Lettering, Striping, Locomotive 268; engine class C-16, narrow gauge engine type 2-8-0, Consolidation per Chicago Rail Fair (Card: 21517 File: M-557), March 26, 1949
Item — OVFF: 79
Dates: March 26, 1949
Std. Gauge...
Lettering, Freight Locomotives; engine class K-59, engine type 2-8-2, Mikado, engine numbers 1200-1213 (Card: 2782 File: L-357), July 26, 1912
Item — Tube: 24
Lettering, Passenger Locomotives; engine class P-44, engine type 4-6-2, Pacific, engine numbers 1001-1006 (Card: 2789 File: L-357 ), December 7, 1912
Tube 24
Lettering on Tender, Back End Sill; engine class M-64, engine type 4-8-4, Northern, engine numbers 1700-17134 (Card: 12086 File: L-154 ), July 22, 1927
Item — OVBox: 17, Folder: 4
Cameron