| Abbreviation | Definition |
|---|---|
| HTSX | Herzog Transit Services |
| HTTX | Trailer Train (TTX Corporation) |
| HTTX | TTX Company |
| HTW | Hoosac Tunnel and Wilmington |
| HUBA | Hudson Bay (BNSF Railway) |
| HUD | Hudson Amtrak Station |
| HUDX | Hudson Technologies |
| HUDX | Hudson Technologies Incorporated |
| HUKU | Huktra |
| HUKU | Huktra NV |
| HUNX | Huntting Elevator |
| HUTX | Hutchinson Transportation |
| HUTX | Hutchinson Transportation Company |
| HVRT | Harlem Valley Rail Trail |
| HWCX | Halliburton |
| HWCX | Halliburton Company |
| HWIU | Healdworks |
| HWPX | Hiram Walker and Sons |
| HWPX | Hiram Walker and Sons Incorporated |
| HYDX | Praxair Incorporated |