AMTK
| Amtrak | 4 |
AOK
| Arkansas-Oklahoma Railroad | 1 |
ATEX
| Asplundh Tree Expert Co Railroad Division | 2 |
ATSF
| Atchison Topeka & Santa Fe | 2 |
BCOL
| Canadian National Railways | 1 |
BN
| Burlington Northern | 25 |
BNSF
| BNSF Railway | 52 |
BO
| Baltimore & Ohio | 2 |
CL
| CL | 1 |
CN
| Canadian National Railways | 20 |
CNW
| Chicago & Northwestern | 9 |
CO
| Chesapeake & Ohio | 6 |
CP
| Canadian Pacific Railway | 29 |
CR
| Conrail | 103 |
CSX
| CSX Railroad | 147 |
DME
| Dakota, Minnesota and Eastern | 1 |
DRGW
| Denver & Rio Grande Western | 4 |
GREX
| Georgetown Rail Equipment Company | 6 |
GTW
| Grand Trunk Western | 3 |
HLMX
| Helm Financial Corporation | 4 |
HZGX
| Herzog Contracting Corporation | 13 |
IATR
| Iowa Traction Railroad Company | 2 |
IC
| Illinois Central | 3 |
ICE
| Iowa Chicago and Eastern | 1 |
ICG
| Illinois Central Gulf | 1 |
INRD
| Indiana Railroad | 1 |
LMIX
| Loram Maintenance of Way Inc. | 14 |
MP
| Missouri Pacific | 12 |
MRL
| Montana Rail Link | 2 |
NP
| Northern Pacific | 1 |
NS
| Norfolk Southern | 351 |
NW
| Norfolk & Western | 111 |
NYC
| New York Central | 2 |
RRVW
| Red River Valley and Western Railroad | 3 |
RWCX
| RWC Incorporated | 18 |
SBD
| Seaboard System | 3 |
SOU
| Southern | 119 |
SPMW
| Southern Pacific Maintenance of Way | 4 |
SPSX
| Progress Rail Services Corp | 2 |
TCWR
| Twin Cities and Western | 1 |
UP
| Union Pacific Railroad Company | 10 |
VSR
| Valley & Siletz RR | 22 |