Auckland mayor Wayne Brown is demanding action to fix the supercity's rail system including "an aggressive plan to fix" heat-affected tracks after 80 trains were cancelled across the commuter network on Monday.
MPs at a select committee at Parliament on Thursday questioned KiwiRail executives and the board chair about why it had got this bad.
The executives said high temperatures played a part on 4.4km out of 200km of track, leading to KiwiRail imposing a speed limit of 30-40km/h, down from 70km/h.
KiwiRail chief executive Peter Reidy told MPs heat "didn't shut the whole line" but it then had a "cascade" effect.
"If the rail is not on good foundations it will buckle more easily," chief capital planning and asset development officer David Gordon said. "Some of the track is not on good formation."
KiwiRail did not cancel the trains, they said, rather it was a call by operators Auckland Transport and Auckland One Rail.
Though the heat impact was on short stretches, speed restrictions added to crewing and timetable complications to "cascade" through into mass cancellations, they said.
It took collective action to address, and the three agencies would be taking an action plan to Auckland mayor Wayne Brown next week, after meeting him on Wednesday to address the question of working better together. The executives said a shared control centre had now opened in Auckland which would help.
Out of 9000 unplanned outages last year on the tracks, 5000 were due to weather and KiwiRail's network problems caused 1600. Track problems accounted for just 1.26 percent of failures, Reidy said.
"The root case is ... the network in parts is run down," KiwiRail board chair David McLean told MPs.
The executives used the word "fragile" but when MP Tom Rutherford said the heat impact appeared to compromise an "extremely fragile" network, they rejected that.
But funding the fixes was beyond KiwiRail's budget, and the model to maintain and upgrade in Auckland Wellington was broken.
Wellington and Auckland metro train operators have told KiwiRail they could afford their part of the maintenance bill, McLean said. They were working on a new model with councils and the Transport Ministry.
Despite the limitations, upgrades were going on which entailed planned shutdowns, such as at the weekend. Auckland was worst hit but would eventually adopt a different approach of shutdowns at night; Wellington would need an alternative approach to keep up maintenance.
The company was prioritising which lines to upgrade. Tracks were okay but "we have issues with bridges", Gordon said. Timber in bridges ideally lasted 18 years but they had some that was 105 years old and needed replacement with concrete.
"We'll look at the risk factors with bridges" and other assets, Reidy said.
Some signalling was at the end of its life.
The executives talked about ramping up investments so they were doing in just five years the sort of upgrades and work that would normally take 40 years. It was beyond what Australian states were investing, Reidy said.
In December last year, the government declined KiwiRail’s request for an extra $1.47 billion for the Inter-island Resilience Connection after the project’s total cost escalated to almost $3 billion.
There are three ships in the Interislander fleet - all of which are increasingly unreliable as they near the end of their working lives.
The government is appointing a ministerial advisory group to provide independent advice and assurance to ministers on future options for the vital transport connection.
However, the future of the ferry service remains unclear.
