| Railroad Name | RailroadInitials |
| American Car & Foundry | AC&F |
| Argentine Central | AC |
| Arizona Copper Co | ACC |
| Baldwin Locomotive Works | BLW |
| Baltimore & Ohio | B&O |
| Buffalo Rochester & Pittsburgh Railway | BR&P |
| Burlington & Missouri River in Nebraska | B&MR in Neb |
| Chicago Burlington & Quincy | CB&Q |
| Chicago Milwaukee & St Paul | CM&StP |
| Colorado & North Western | Colo&NW |
| Colorado & Southern | C&S |
| Colorado Central | CC |
| Colorado Fuel Co | CFC |
| Colorado Midland | CM |
| Conoco | CONX |
| Cripple Creek & Colorado Springs | CC&CS |
| Crystal River | CRR |
| Cumbres & Toltec Scenic | C&TS |
| Denver & Interurban | D&I |
| Denver & Rio Grande | D&RG |
| Denver & Rio Grande Western | D&RGW |
| Denver & Salt Lake | D&SL |
| Denver & Swansea | D&S |
| Denver Boulder & Western | DB&W |
| Denver South Park & Pacific | DSP&P |
| Denver Tramway | DT |
| Flint & Pere Marquette | F&PM |
| Florence & Cripple Creek | F&CC |
| Gilpin Tramway | GT |
| Kansas & Gulf Short Line | K&GSL |
| Midland Terminal | MT |
| mining | mining |
| Minneapolis St Paul & Sault Ste Marie | MStP&SSteM |
| Missouri Pacific | MP |
| Montana Southern | MtS |
| Nevada-California-Oregon | NCO |
| New York Central | NYC |
| none | unknown |
| Norfolk & Western | N&W |
| Phelps Dodge Corp | PD |
| Philadelphia & Reading | P&R |
| Pullman | Pullman |
| Rio Grande Southern | RGS |
| Rio Grande Western | RGW |
| several | several |
| Silverton Gladstone & Northerly | SG&N |
| Silverton Northern | SN |
| Southern Pacific | SP |
| Sumpter Valley | SV |
| Texaco | TCX |
| Uintah | URy |
| Union Pacific | UP |
| Union Tank Line | UTLX |
| Wisconsin Central | WC |