AMTK
| Amtrak | 11 |
BCT
| BCT | 1 |
BO
| Baltimore & Ohio | 1 |
CG
| Central Of Georgia | 1 |
CP
| Canadian Pacific Railway | 1 |
CR
| Conrail | 2 |
DELT
| DELT | 1 |
DLCR
| DLCR | 2 |
GREX
| Georgetown Rail Equipment Company | 5 |
HARS
| HARS | 1 |
HVRX
| Heber Valley Historic Railroad | 1 |
HZGX
| Herzog Contracting Corporation | 1 |
LBFX
| L B Foster Co | 4 |
LMIX
| Loram Maintenance of Way Inc. | 34 |
MEC
| Maine Central | 1 |
NJT
| New Jersey Transit | 12 |
NS
| Norfolk Southern | 17 |
NW
| Norfolk & Western | 2 |
RCC
| RCC | 2 |
RDG
| Reading Railroad | 3 |
RJC
| RJC | 1 |
SDIX
| Steel Dynamics, Inc | 4 |
SLRS
| SMS Rail Service Incorporated | 2 |
SOU
| Southern | 1 |
SPAX
| Southeastern Pennsylvania Transportation (SEPTA) | 17 |
SRNJ
| Southern Railroad Company of New Jersey | 1 |
SRS
| Sperry Rail Service | 2 |
UP
| Union Pacific Railroad Company | 1 |
UTAH
| Utah Railway | 1 |