Sydney commuters who suffered financially as a direct result of massive delays and chaos on the city's rail network could be eligible for compensation.
A train on the north shore line needed mechanical repairs on Friday after an open train hatch was spotted by the driver about 5.30am at Town Hall.
The flow-on disruptions extended into the evening peak with city workers facing a chaotic train system and gridlocked road network.
Passengers were held up at Town Hall after 5pm as staff closed ticket barriers with long queues forming as commuters waited for their turn to enter the station.
Video shot at Central Station and posted to Twitter about 4.30pm showed a platform crammed with people trying to beat rush hour.
Sydney Trains chief executive Howard Collins said the hatch that started the chaos was very close to 1500 volts of direct current power and could have caused days of damage if left unchecked.
"It could have brought all the wiring down in the city ... we could have gotten stuck over the Harbour Bridge," he told reporters.
Commuters were left languishing on trains or queuing for buses for hours as officials worked to repair the fault. Some were even told to try walking across the Harbour Bridge instead of waiting.
Sydney Trains ahead of the evening peak warned services across the network were still recovering and wouldn't run on time.
Sydney Trains on Friday evening opened a window for possible compensation.
"Customers who suffered significant financial hardship, such as a missed flight, as a direct result of service delays this morning may be eligible to make a claim for compensation," the spokeswoman said in a statement on Friday evening.
"Any potential claims will be assessed on a case by case basis."
Vehicle traffic in and out of Sydney's CBD was gridlocked after 5pm but by 7pm had eased slightly, with the heaviest traffic in the inner east and inner south.
Mr Collins apologised for the widespread delays but believed his team made the right call in stopping the train.
What caused the hatch to open is being investigated but early signs point to wind or a tree branch hitting the train.
In order to fix the hatch, power to the line had to be switched off - which involved sending workers down tunnels to pull isolation switches.
Mr Collins revealed those switches were put in place in the 1920s or 30s and were "almost Frankenstein in their look".
"It is a failure of the way our system is built that one train can stop the entire network," he said.
Australian Associated Press