| Abbreviation | Definition |
|---|---|
| HRLZ | Hudson Railway Equipment Company |
| HROX | Hanson Aggregates |
| HRRC | Housatonic Railroad |
| HRRC | Housatonic Railroad Company |
| HRRX | Conrail (On-Track Railcar Services) |
| HRRX | On-Track Railcar Services Incorporated |
| HRS | Hamburger Rail Service |
| HRS | Holidaysburg and Roaring Spring Railroad Company |
| HRS | Hollidaysburg and Roaring Spring Railroad |
| HRSX | Harbor Rail Services of California |
| HRT | Hartwell Railroad |
| HRT | Hartwell Railroad Company |
| HRZU | Matson Navigation |
| HS | H and S Railroad Company Incorporated |
| HS | Hollands Spoor railway station |
| HS | Housatonic Southern (H and S Railroad) |
| HSCX | Hammond Standish (Steel Wheels) |
| HSCX | Steel Wheels Limited |
| HSE | Heavy Stock Enabled |
| HSFZ | Atchison Topeka and Santa Fe Railway |