"Unbuilt" is where you'll find locomotives which had been planned but never constructed!
You'll find the following locomotives:
| Class | Built | Builder / Type | Numbers | Miscellaneous |
| 38 | Unbuilt | Type 3 | 38001-38250 | Planned for Railfreight |
| 48 | Unbuilt | Type 4 | 48xxx | Planned Mixed Purpose Locos |
| 61 | Unbuilt | Type 5 | 61001-61220 | Became Class 66 |
| 62 | Unbuilt | GM Type 5 | 62xxx | Planned for Railfreight |
| 65 | Unbuilt | Type 5 | 65xxx | |
| 68 | Unbuilt | GM / Bombardier | 68001-68036 | Planned for Virgin XC |
| 88 | Unbuilt | AC Electric | 88xxx | Planned for Railfreight |
| 93 | Unbuilt | AC Electric | 93001-93032 | Planned for IC250 |