| Abbreviation | Definition |
|---|---|
| JDSX | M and C Railcar Leasing |
| JDSX | M and C Railcar Leasing L.L.C. |
| JE | Jerseyville and Eastern (Joppa and Eastern Railroad) |
| JE | Joppa and Eastern Railroad Company |
| JECX | Western Resources |
| JECX | Western Resources Incorporated |
| JEF | Jefferson City Amtrak Station |
| JEFW | Jefferson Warrior Railroad |
| JEFW | Jefferson Warrior Railroad Company |
| JEPX | PSI Energy |
| JFDX | W. K. Horney (First Union Rail) |
| JGLU | Juglinija Lines |
| JGRU | John G. Russell Transport |
| JGRU | John G. Russell Transport Limited |
| JGS | James Griffiths and Sons |
| JHMX | Alabama Power |
| JHMX | Alabama Power Company |
| JHPX | Huntsman Chemical Corporation |
| JHPX | Huntsman Chemical Corporation (NOVA Chemicals) |
| JJJX | JJ Rail Car Leasing Limited |