On 30th March 2016 Snaefell Mountain Railway no. 3 ran away from the Summit with no crew or passengers on board before derailing shortly before the stop at Bungalow, leaving the tracks and being more or less destroyed on the mountain side. Although an investigation had been undertaken the results of this had not been released publically but a Freedom of Investigation request by the Isle of Man Newspapers has now seen further details revealed of what caused no. 3 to runaway. It has been confirmed that both parking brakes on the tram had failed which, coupled with the temporary arrangements at the Summit owing to overrunning construction works, led to the tram heading down the mountain.
When the incident happened works at the Summit on the paved area for passengers to board and alight were still ongoing which meant when there were two trams present one had to be moved away from outside the Summit Hotel onto the down line allowing the second arrival to let its passengers off. This is what happened with no. 3 and although crews are aware they shouldn’t leave their trams unattended on the running line the motorman did leave the tram although he did apply the parking brake and locked the vehicle to ensure no passengers could board.
Following the runaway and subsequent derailment the investigation discovered that there was damage to brakes at both ends. There was said to be signs of wear or damage in the ratchet wheel at one end of the tram with the other end said to have had a fracture. However it is not known if this happened before or during the crash. Ian Longworth, Public Transport Director, is quoted in the Isle of Man Newspapers as saying that the brake failure was irrelevant to the cause of the runaway/derailment.
The investigator did say that changes to the trackwork at the Summit could have contributed to the incident as with it stabled on the down line this was at a slight downward gradient whereas normally it would have been stabled on the flat in the station area.
In summary the report questioned the recording of inspections and maintenance of the brakes on the trams and also failures in the way changes to the infrastructure of the line were managed.