Canberra's light rail operator will review the causes behind an unspecified "technical issue" that prevented vehicles leaving the depot, causing delays on Thursday morning.
Canberra Metro, which oversees the capital's light rail network, blamed the disruption on a technical issue on the alignment.
Angry commuters expressed frustration on social media, asking what an "alignment" was and why the issue wasn't announced to passengers at stops across the network.
A Canberra Metro spokesman said the alignment was the rail route and the technical issue had only affected one vehicle, which delayed other vehicles leaving the Mitchell depot.
"Because some vehicles were delayed leaving the depot, the vehicles ran at a reduced frequency," the spokesman said.
Some buses helped passengers stranded along the network while other vehicles were put into service.
Despite some commuters complaining they hadn't been notified on board the trams or at designated stops, the spokesman said announcements had been made.
"Canberra Metro acknowledges the feedback from customers regarding the frequency of service announcements during this morning's disruption," the spokesman said.
"We are reviewing our procedures with the aim of improving our service and ensuring our customers are kept informed of any changes to light rail services."