"Disappointed" passengers were stranded at train stations across Tāmaki Makaurau/Auckland again on Thursday, after a signalling fault caused "unbelievable" delays.
One passenger told Newshub they arrived at Panmure Station at 8am and waited nearly an hour for a train to Waitematā Station (Britomart).
"Trains were going south to Manukau but none [were] going north," they claimed.
An Auckland Transport (AT) announcement said there would be a 10-minute delay.
"There [were] about 200 passengers at Panmure on Platform 1 waiting," the person told Newshub.
When the train eventually arrived at 8.50am, it was "so full people were standing crammed in the aisles".
An AT spokesperson told Newshub nine train services were cancelled on Thursday morning, due to a signalling fault at Puhinui.
"Although the issue was fixed by maintenance crews by 6:40am it had flow-on effects for some of our later services because trains and crews had been displaced and were not where they needed to be to keep running services to our timetable," the spokesperson said.
The transport authority hadn't been promptly alerted to the issue affecting services on the Eastern and Southern Lines, the spokesperson added.
"Our customer communications team did not receive the usual notification about these cancellations, which meant we weren’t able to provide our customers with the same level of information about the disruption that we usually would."
AT said it's working with its rail operator to ensure teams are "promptly informed" of future disruptions.
Jon Knight, KiwiRail's metros general manager, told Newshub damage to infrastructure related to the signals system was discovered at Puhinui on Thursday morning.
"While it was fixed by 6:35am, earlier trains had to be manually guided through the section of track, which slows down train services," Knight said.
"Disruption management is a critical part of running the metro network and KiwiRail, Auckland Transport and Auckland One Rail have operations centres to manage the timetable and incidents," said Knight.
Auckland One Rail decides on cancellations, not KiwiRail, he clarified.
He said all three agencies communicate and plan together when disruptions happen, which is "standard practice and was the process we followed".
"This morning it appears there may have been a delay in communicating disruption incident information between parties."
A review is underway, he said.
One key development for the city is the new Auckland Rail Operations Centre (AROC), due to open in late March, Knight said.
The AROC will be a central location for all three agencies to better manage the metro rail network.
"It will also include the relevant customer communications teams, enabling more timely communications to commuters," Knight said.