| Abbreviation | Definition |
|---|---|
| QCCX | Equistar Chemicals LP |
| QCCX | Quantum Chemical Corporation |
| QCGU | Quest Capital Group |
| QCR | Quebec Central Railway |
| QCRT | Queen City Rail Trails |
| QFFX | Quimica Fluor |
| QFFX | Quimica Fluor, S. A. de C. V. |
| QGR | Quebec Gatineau Railway |
| QGR | Queensland Government Railways |
| QGRY | Quebec Gatineau Railway |
| QGRY | Quebec Gatineau Railway Incorporated |
| QJX | Qingdao Japan Express |
| QMO&O | Quebec, Montreal, Ottawa, and Occidental |
| QNS&L | Quebec North Shore and Labrador Railroad |
| QNSX | Rail Enterprises Inc. dba Quebec North Shore and Labrador Railway |
| QOCX | GE Rail Services |
| QOCX | Quaker Oats Company |
| QOHX | Quaker Oats |
| QOHX | Quaker Oats Company |
| QOPX | General Electric Rail Services Corporation |