| Clue | Source | Date |
|---|---|---|
| Train units with no sides or top | ||
| Sideless freight carriers | Wall Street Journal | 22 Aug 2016 |
| Vagabonds' transportation, maybe | ||
| Freight carriers | ||
| Freight components | ||
| Freight components | ||
| Vagabonds' transportation, maybe | ||
| Some train units | ||
| Freight train components |