| Abbreviation | Definition |
|---|---|
| IRIMEE | Indian Railways Institute for Mechanical and Electrical Engineering |
| IRIMEE | Indian Railways Institute of Mechanical and Electrical Engg |
| IRIMEE | Indian Railways Institute of Mechanical and Electrical Engineering |
| IRLX | Inter-RailLilnk |
| IRLX | Western Railroad Supply |
| IRM | Indiana Railway Museum |
| IRMZ | III Transportation |
| IRMZ | Iowa Interstate Railroad Limited |
| IRN | Consolidated Rail Corporation (formerly Ironton Railroad Company) |
| IRN | Ironton Railroad (Conrail) |
| IRNU | Seacube Container Leasing |
| IRPS | Indian Railway Personnel Service |
| IRPS | Indian Railway Personnel Services |
| IRRC | Iowa Railroad |
| IRRC | Iowa Railroad Company |
| IRRS | International Rail Road Systems |
| IRRS | International Rail Road Systems Incorporated |
| IRSS | Indian Railway Stores Services |
| IRSSE | Indian Railway Services of Signal Engineers |
| IRSZ | Interpool Rail Services |