A 'high risk' stretch of rail in Wellington could lead to deaths, experts have found, reiterating earlier calls for more safety measures on the back of four investigations into passenger trains that almost crashed.
A new risk report has examined a busy stretch of rail where multiple tracks converge in the 750m approach to Wellington Station and there were 67 cases of trains passing signals they shouldn't have, in less than five years.
It was produced by independent engineers for KiwiRail, which are responsible for the tracks, rail corridor and signals throughout the country. The state-owned enterprise is now planning improvements.
However, the report follows previous safety warnings about increasing risks in this area since 2013 by the Transport Accident and Investigation Commission (TAIC) after four near-crashes, each where two trains almost collided in places where tracks converge near the station.
In the most recent of those near-misses, last year a 6.10pm service from Wellington "loaded" with people and headed to Waikanae was unable to be stopped because of a signals flaw in the system, and continued to travel toward a junction about to be crossed by another peak hour train.
It was stopped by a staff member on board 120m past the planned stop point.
In a 2016 close call a driver missed a red light then stopped their train 12m short of a rail merging point that was crossed just 13 seconds later by a train carrying 79 passengers to the Hutt Valley.
KiwiRail did introduce new short-term safety measures following the four near-crashes, including reviews and fixing specific glitches found in the system.
But the commission reports said other recommended and "reasonable measures had not been taken to further reduce the risk of trains colliding", and "more work was required of KiwiRail".
The new report, obtained by RNZ under an Official Information Act request, said between 2011 and late 2015 there were 67 reports of dangerous situations created because signals were passed by mistake in the Wellington region.
Of these, 21 percent were in the Wellington Station area covered by the report.
The engineers followed the previous investigators in emphasising the dangers posed by the area, which it calls a "complex junction with very tight track and signal space constraints" in a crowded space on the waterfront.
The reason there have been no recent crashes in this area was probably due to skilled signals operators, a low speed requirement for drivers leaving the station and a "robust right of way process", the new report said.
Rail Infrastructure Consultants, who produced the new report, explained their "high risk" finding for the area was because while a train crash was "unlikely", the consequences of a train missing a signal and hitting another train in this area could be "catastrophic" and result in injuries or deaths.
KiwiRail had a legal obligation to plan for human errors to happen and look at safety enhancements "so far as is reasonably practical", they said.
And more train services are expected to be needed in the future, which would put more pressure on the congested area.
In the short-term the report recommends reviewing speeds, reinforcing signals processes, and installing train stops in some places - an automatic halt on any train travelling past a mark it should not pass.
But more effective long-term solutions depend on KiwiRail replacing its outdated mechanical Lever Frame signals system, so more sophisticated 'Automated Train Protection' controls can be programmed, including train stops at all signal points.
However it notes this would be "several years away".
In response to the report's release a KiwiRail spokesperson said it has "robust mitigation" in place at Wellington Station and it was rare for trains to pass required stop points accidentally.
"The current system operates with a high level of safety.
"However the report was commissioned to assist KiwiRail to understand where safety enhancements could be made, in the interests of continuous improvement."
Speeds will be reviewed for this area, a train stop will be trailed at one point, and it is taking part in an investigation of health and safety at Wellington Station along with with Greater Wellington Regional Council, and Transdev, which operate Wellington's passenger trains.
It also has plans introduce an modern Automatic Train Protection system, similar to one used in Auckland's metro rail network, and plans to present a business case to the Ministry of Transport for this, next year.
"To deliver it would be a multi-year and multimillion dollar undertaking."