AGR
| Alabama and Gulf Coast | 2 |
ARR
| Alaska Railroad | 7 |
BCOL
| Canadian National Railways | 2 |
BN
| Burlington Northern | 3 |
CSX
| CSX Railroad | 3 |
CWWR
| Chehalis Western | 1 |
LN
| Louisville & Nashville | 5 |
MKT
| Missouri-Kansas-Texas | 2 |
MP
| Missouri Pacific | 1 |
SOU
| Southern | 2 |
SROX
| U.S. DOE, Savannah River Operations | 2 |
WFS
| West Isle Line Incorporated | 1 |