| Abbreviation | Definition |
|---|---|
| KFMX | Oils Unlimited |
| KFPX | Koppers |
| KFR | Kettle Falls International Railway |
| KFTX | J and J Railcar Leasing |
| KGCX | INDSPEC Chemical Corporation |
| KGCX | Koppers (INDSPEC Chemical Corporation) |
| KGFX | Kingsford |
| KGFX | Kingsford Company |
| KGJ&E | Kanawha, Glen Jean, & Eastern Railway |
| KGLX | Commonwealth Edison |
| KGRX | Kasgro Rail Corporation |
| KIIX | Koppers Industries |
| KIN | Kingston Amtrak Station |
| KIS | Kissimmee Station (SunRail- AMTK) |
| KJR | Berkman Rail Services Incorporated - Kiski Junction Railroad |
| KJR | Kiski Junction Railroad |
| KJRY | Keokuk Junction Railway |
| KKLU | K Line |
| KKLZ | K Line |
| KKRR | Knox and Kane Railroad |