| Abbreviation | Definition |
|---|---|
| GT | Grand Trunk |
| GT | Grand Trunk Railroad |
| GT | Grand Trunk Railway |
| GTA | Georgia, Tennessee, and Alabama |
| GTA | Grand Trunk Western (Canadian National Railway) |
| GTA | Grand Trunk Western Railroad Incorporated |
| GTAX | Harvest States Cooperative |
| GTC | Gulf Transport |
| GTER | Grafton Terminal Railroad |
| GTEU | General Transport Equipment |
| GTEU | General Transport Equipment Company, Inc. |
| GTIS | Guilford Transportation Industries |
| GTIZ | G. T. Intermodal U S A |
| GTIZ | G. T. Intermodal USA |
| GTLZ | G. T. Leasing |
| GTMU | GTM Manufacturing |
| GTP | Grand Trunk Pacific Railway |
| GTPR | Grand Trunk Pacific Railway |
| GTPZ | TIT Services |
| GTR | Govia Thameslink Railway |