A Labor-led committee will scrutinise the problem-plagued light rail system in Sydney's inner west.
The parliamentary inquiry comes after cracks were found in all 12 vehicles used on the L1 line, forcing commuters onto replacement buses and ferries.
"With light rail services suspended from Central to Dulwich Hill for up to 18 months, thousands of individuals and businesses have been significantly impacted," committee chair Daniel Mookhey said.
"The committee seeks to shed light on how and why this has happened, its impact on the community, and importantly, how those impacts can be mitigated until the line is reinstated."
The inquiry will also examine services in Sydney's southeast and Newcastle as well as the procurement, operation and maintenance of the systems.
Hearings will be heard in the new year, with submissions and a questionnaire closing on March 31.
Outgoing Transport Minister Rob Stokes announced last month that all 12 trams on the city's inner west line would be decommissioned for up to 18 months to fix major cracks - up to 30cm long - on the rolling stock.
But last week he revealed the seven-year-old light rail cars would be back up and running in less than a year.
In the meantime, services running every 15 minutes will progressively resume from as early as February, with trams borrowed from the CBD and southeast light rail lines.
Former police minister David Elliot will take over the transport portfolio from Tuesday after Premier Dominic Perrottet's first major cabinet reshuffle.
