There is evidence of a Standard 4 Mogul 2-6-0 traversing the line.
 Trawsfynydd Lake Halt with a standard 4 mogul. Stwlan dam in distance. |  Standard Class 4 Tank 80104 under the footbridge at Bala Town station | |
| Locomotive Number | Build Date (Batch) | Location Built | Notes |
| ? | Mogul 2-6-0 Locomotive | ||
| 80104 |