AOK
| Arkansas-Oklahoma Railroad | 1 |
BNSF
| BNSF Railway | 1 |
BTCX
| Browner Turnout Company | 1 |
CW
| Colorado and Wyoming | 1 |
GIMX
| General American Marks Company | 2 |
ITTX
| TTX Company | 22 |
PEYX
| Transportation Technology Services Inc | 9 |
PTTX
| TTX Company | 7 |
QUAX
| Redstreak, LLC | 1 |
SP
| Southern Pacific | 1 |
SSW
| St Louis Southwestern (Cotton Belt) | 1 |