On Sunday 21 October 2018, four special freight cars used to transport military material rolled out from the Auma branch line and onto the Rørosbanen line.
On 19 and 20 October 2018, three empty freight car sets consisting of special freight cars to transport military materiel were parked on the Auma branch line. The freight cars were parked there in connection with the NATO exercise Trident Juncture.
On Sunday 21 October, one of the sets consisting of five freight cars started to roll uncontrolledly. The first two freight cars rolled across a snow shield, through a derailer and onto the Rørosbanen line. Freight car number three derailed on the derailer and stopped the freight car set from moving further.
The parking of rolling stock on the Auma branch line took place during the period from the morning of Friday 19 October until the early hours of Saturday 20 October. The last freight car set was to be parked on track 2. It had to be split up and placed on either side of a pedestrian crossing.
Some of the freight cars were not equipped with parking brakes, and the signaller only found parking brakes on the freight car set to be parked south of the pedestrian crossing. There were two brake shoes available, and it was decided to use them on either side of the pedestrian crossing to prevent the freight cars from rolling towards it.
The signaller believed the track to be completely level. The main line and the control valves were not emptied of air when the freight car sets were parked, but the signaller released some air from the main line.
The freight cars rolled onto the Rørosbanen line on Sunday 21 October, some time between 10:30 and 11:00, causing the section of track to be identified as occupied.
The traffic controller first attempted to release the track by issuing a ‘simulated train passage’ order in the remote control system. The section of track was still registered as occupied, giving indication of a technical fault.
The traffic controller therefore had to give southbound regional train 2384 a verbal order to proceed from Tynset to Alvdal. When the train approached Auma, the train driver saw the freight cars on the main track. Because the train had been given an order to proceed with speed restrictions, there was never any danger of a collision.
Snow shields are often used in winter to protect the derailers from rain, snow and ice. A locally produced snow shield made of 3.3-mm-thick steel plates was used at Auma. The strength of the shield meant that, instead of being crushed, it was only deformed, serving as a guide rail guiding the first wheels over the derailer.
The Accident Investigation Board Norway (AIBN) proposes one safety recommendation. It concerns recommending traffic operators to strengthen their procedures to ensure that the brakes on freight cars are properly engaged when parked. ■