Train Dates for 1966.
(Note: Belfast YR = Belfast York Road; Belfast CSD = Belfast Central Services Depot; Belfast GVS = Belfast Great Victoria Street; ECS = Empty Coaching Stock; LE = Light Engine; GM = Railway company diesel locomotive; Whitehead generally means the RPSI's own Whitehead Excursion Station.)
| Date | Train/Operation | Loco | Itinerary/Route | Special Notes |
| 14/05 | Province Of leinster | 54: Belfast GVS - Dromin Junction 49: Dromin Junction - Ardee - Drogheda - Kingscourt - Drogheda 54: Drogheda - Belfast GVS |
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| 14/05 | Engine Transfer | Adelaide - Lisburn - Ballymena | No.171 hauled B&CDR horsebox, open wagon, Inglis bread container (on a flat wagon) and 186 (out of steam) to Ballymena for storage. | |
| 29/09 | Light Engine | Ballymena - Belfast YR | First working as an RPSI engine. | |
| 07/10 | Light Engine | Belfast YR - Carrickfergus & return | Test run. | |
| 08/10 | Autumn Outing | Belfast YR - Larne Harbour & return | First rail tour worked by an RPSI owned engine. |