Passenger Rail, Safety, Standards & Regulation

Gap between insulated joint and signal highlighted in near-collision investigation

An eight-metre gap between a signal and its insulated joint contributed to a near collision between passenger trains at Wellington Railway Station in May last year, New Zealand’s accident commission has said.

The Transport Accident Investigation Commission released its findings this week into the incident on May 15, 2017.

Shortly after leaving Wellington station, the driver of a loaded metropolitan passenger train thought there may be an issue with the train’s brakes. After a discussion with maintenance staff, it was decided to return the train to Wellington Station.

However, TAIC’s investigation found the driver had stopped the train, such that the rear driver’s cabin had crossed the insulated joint for Signal 39, but had not passed the signal itself.

This meant when the driver arrived in the rear cabin, to return to Wellington Station, he could not see Signal 39 as it was behind him. But because the train had passed over the insulated joint, the signaller’s mimic screen indicated the train had passed Signal 39.

The signaller, planning to use Signal 39 to hold the train on its return journey, until another inbound train was clear, directed the driver to move towards that Signal.

The driver then advanced the train, looking for Signal 39, which was already behind him.

Soon after the train began moving, it crossed back over the insulated joint in the rail, and the signaller saw on the train had passed Signal 39 on the mimic screen.

The signaller called the driver to stop the train, and the train stopped about 120 metres past the red signal.

There was no collision and nobody was injured.

Along with the gap between the insulated joint and the signal, the TAIC identified two safety issues that had been identified in a previous inquiry:

  • there is a heightened risk of trains colliding within the approaches to Wellington Station because limited space makes the track layout congested, and;
  • a number of reasonable measures had not been taken to further reduce the risk of trains colliding in the approaches to Wellington Station.

“The key safety lesson arising from this accident is that trains should not be unnecessarily authorised to proceed up to red signals in congested areas, because the reduced safety margins in these areas increase the risk of a collision if a signal is passed at danger,” the Commission noted.