| Abbreviation | Definition |
|---|---|
| QOPX | General Electric Railcar Services Corporation |
| QOTX | Great Lakes Chemical Corporation |
| QOTX | Quaker Oats Chemicals Division |
| QPCX | General Electric Rail Services Corporation |
| QPCX | General Electric Railcar Services Corporation |
| QRC | Quebec Railway Corporation |
| QRC | Quebec Railway Corporation Incorporated |
| QRR | Quincy Railroad |
| QRR | Quincy Railroad Company |
| QRSX | Quality Railway Services and Supply |
| QRSX | Quality Railway Services and Supply Company |
| QRTC | Quinton Rail Technology Centre |
| QSMX | Quaker State Corporation |
| QSMX | Quaker State Oil Refining Corporation |
| QSOX | Quaker State Oil Refining Corporation |
| QSR | Bangor and Aroostook Railroad (Montreal, Maine & Atlantic) |
| QSR | Quebec Southern Railway |
| QTL | Quincy and Torch Lake Railroad |
| QTTX | TTX Company |
| QTTX | TTX Corporation |