ARR
| Alaska Railroad | 7 |
ATSF
| Atchison Topeka & Santa Fe | 3 |
BN
| Burlington Northern | 8 |
BNSF
| BNSF Railway | 1 |
CBQ
| Chicago Burlington & Quincy | 2 |
CNW
| Chicago & Northwestern | 13 |
CP
| Canadian Pacific Railway | 6 |
DOTX
| USDOT/Federal Railroad Administration | 3 |
GN
| Great Northern | 14 |
IC
| Illinois Central | 9 |
INLX
| Incoal Company | 6 |
ISCX
| ISC Incorporated | 4 |
MILW
| Milwaukee Road | 32 |
MRL
| Montana Rail Link | 1 |
NP
| Northern Pacific | 1 |
RAC
| RAC | 1 |
SOO
| Soo Line | 14 |
SOU
| Southern | 1 |
SP
| Southern Pacific | 1 |
TBCX
| Boeing Company | 4 |
UP
| Union Pacific Railroad Company | 4 |
UTAX
| Utah Frontrunner | 1 |
WIM
| WIM | 1 |
YVT
| Yakim Valley Transportation Company | 4 |