AAR
| Association of American Railroads | 4 |
ATSF
| Atchison Topeka & Santa Fe | 1 |
CBH
| CBH | 1 |
CR
| Conrail | 1 |
DOTX
| USDOT/Federal Railroad Administration | 7 |
FEC
| Florida East Coast | 1 |
MILW
| Milwaukee Road | 1 |
NS
| Norfolk Southern | 4 |
RDG
| Reading Railroad | 2 |
SPAX
| Southeastern Pennsylvania Transportation (SEPTA) | 1 |
UP
| Union Pacific Railroad Company | 1 |