ARR
| Alaska Railroad | 3 |
BNSF
| BNSF Railway | 7 |
CNW
| Chicago & Northwestern | 1 |
CR
| Conrail | 22 |
DH
| Delaware & Hudson | 4 |
LMIX
| Loram Maintenance of Way Inc. | 1 |
MEC
| Maine Central | 1 |
MRL
| Montana Rail Link | 3 |
NS
| Norfolk Southern | 47 |
NW
| Norfolk & Western | 1 |
NYC
| New York Central | 1 |
PC
| Penn Central | 1 |
SOU
| Southern | 1 |
SPMW
| Southern Pacific Maintenance of Way | 4 |
ST
| Springfield Terminal | 1 |
UP
| Union Pacific Railroad Company | 3 |