| Abbreviation | Definition |
|---|---|
| HCPX | Occidental Chemical Corporation |
| HCPX | Occidental Chemical Corporation (Hooker Industrial and Specialty Chemicals) |
| HCRC | Hillsdale County Railway |
| HCRR | Honey Creek Railroad |
| HCRR | Honey Creek Railroad Incorporated |
| HCRY | Huron Central Railway |
| HCSX | Helm Chesapeake |
| HCTX | Hallett Construction (Martin Marietta Corporation) |
| HCTX | Martin Marietta Corporation |
| HCYR | Horry County Railway |
| HCZU | Harding Containers International |
| HDM | Hudson and Manhattan |
| HDMU | Hyundai Merchant Marine (America) |
| HDMU | Hyundai Merchant Marine (America) Incorporated |
| HDMZ | Hyundai Merchant Marine (America) |
| HDMZ | Hyundai Merchant Marine (America) Incorporated |
| HDSX | Rail America Equipment Corporation |
| HDSX | RailAmerica Equipment Corporation |
| HE | Hollis and Eastern Railroad |
| HE | Hollis and Eastern Railroad Company |