The engine of the scheduled train overturned, and the connection to its tender was lost. This train was also fitted with 'simple' (non-automatic) continuous vacuum brakes, and these were lost when the engine became disconnected. The train split into two sections, both running back down the gradient towards Armagh. Application of the handbrakes on the tender and on the brake van brought the front and rear halves of the scheduled train to a stop without further incident, a witness telling the inspector "The tender was slightly damaged, but none of the vehicles, and I heard from the guard that a horse in the box next the tender was not injured".