Sydney Trains has opened a window to compensation for commuters who suffered "significant financial hardship" as a direct result of massive delays across the network.
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.
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.
The flow-on disruptions extended into the evening peak with city workers facing a chaotic train system and gridlocked road network.
Sydney Trains chief executive Howard Collins said the hatch that started the chaos on Friday morning 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.
Sydney Trains said any potential claims for compensation will be assessed on a "case by case basis."
"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," a spokeswoman said in a statement on Friday evening.
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.