The summary of findings was released to Radio New Zealand, which first reported the details below. KiwiRail has been using remote-controlled locomotives for shunting for around 10 years. The locomotives are controlled by an operator with a ‘belly pack’, who can view shunting operations from the ground and travel on the locomotive’s footplate.

KiwiRail’s investigation found that the locomotive’s brakes were not applied when the remote operator left the work area to find his mobile phone and call a container terminal. The locomotive control system is designed to apply the brakes automatically after a certain period of inactivity. However, this ‘vigilance alarm’ can be overridden with a key, and the operator had opted to override the alarm during his shift.

When the remote operator left the work area, the locomotive started to roll and travelled 140m across the yard to the ferry linkspan. There was no vessel at the linkspan and the locomotive and two tank containers rolled into the harbour. Evidently, there was no method in the locomotive control system to detect that it was in motion and travelled a large distance without an operator command to apply the brakes.

KiwiRail’s investigation found no issues with the working of the remote-control system. The operator had been certified for remote operation and had four months experience but had not completed monthly safety observations required during his first three months of service. KiwiRail is currently redesigning its inter- island ferry terminals as part of an upgrade process. It is now considering engineering solutions to protect personnel and equipment, as well as modifying its remote- control systems to prevent unwanted movement, and addressing the training process.