| Abbreviation | Definition |
|---|---|
| TIRL | Tonawanda Island Railroad Incorporated |
| TIRZ | Union Pacific Railroad |
| TIRZ | Union Pacific Railroad Company |
| TISH | Tishomingo Railroad |
| TISX | Trinity Industries Leasing |
| TJRX | S. M. Brooks |
| TKCU | ABS Pacific |
| TKCU | ABS Pacific (Concert) |
| TKCX | Thiele Kaolin |
| TKCX | Thiele Kaolin Company |
| TKEN | Tennken Railroad |
| TKEN | Tennken Railroad Company Incorporated |
| TLAU | Trail-Con Leasing |
| TLAU | Trail-Con Leasing Incorporated (Canadian Pacific Limited) |
| TLAZ | Trail-Con Leasing |
| TLAZ | Trail-Con Leasing Incorporated |
| TLCX | General Electric Railcar Services Corporation |
| TLCX | Pullman Leasing |
| TLDX | General Electric Railcar Services Corporation |
| TLDX | Pullman Leasing (GE Capital Railcar Services) |