AMTK
| Amtrak | 6 |
AR
| Aberdeen and Rockfish | 1 |
ATS
| ATS | 2 |
CR
| Conrail | 1 |
CSX
| CSX Railroad | 14 |
ET
| ET | 2 |
GMS
| GMS | 3 |
GREX
| Georgetown Rail Equipment Company | 17 |
LMIX
| Loram Maintenance of Way Inc. | 10 |
NS
| Norfolk Southern | 13 |
NW
| Norfolk & Western | 5 |
RG
| RG | 2 |
SAL
| Seaboard Air Line | 1 |
SBD
| Seaboard System | 1 |
SCL
| Seaboard Coast Line | 2 |
SCLV
| SCLV | 1 |
SOU
| Southern | 21 |
SRS
| Sperry Rail Service | 7 |