Auckland Mayor Len Brown has demanded an explanation from KiwiRail after two rail problems in little more than 12 hours caused commuter chaos.
A broken communications cable caused major delays on Auckland's southern and eastern train networks this morning and hundreds of commuters were held up last night when a signal failure cut stopped trains and left passengers stranded in the CBD.
KiwiRail has apologised for the disruption and launched investigations into the two unrelated incidents, but Mr Brown said today he wanted an explanation and an assurance that everything was being done to prevent it happening again.
"As Aucklanders look forward to electrification and the arrival of our new train fleet, they need confidence that train services are reliable and on time."
Auckland rail operator Veolia Transport said a cable was cut overnight, affecting all train services between Pukekohe and Puhinui this morning.
Commuters were advised to seek alternative transport.
Last night's fault in Auckland happened about 6.30pm at the end of peak-hour traffic, causing people to pour out of the station searching for buses and taxis.
KiwiRail chief executive Jim Quinn said his organisation had launched investigations into both incidents.
"We understand how much frustration this disruption will have caused people who rely on the trains, and we sincerely apologise for that."
Work was underway to repair the fibre optics cable damaged near Papakura as quickly as possible, so normal rail services could be restored.
Mr Quinn said KiwiRail would be working to understand how the incident occurred while works was being done on installing the overhead masts and wires required to power Auckland's new electric trains.
Technical teams were also working to understand the cause of last night's signalling fault, Mr Quinn said.
"It was a local Auckland fault, and with complex equipment such as that it can take some time to pinpoint the cause."