Inquiry chair Lord Hardie was appointed in June 2014 to look into what went wrong with the £776 million project. The inquiry team has had to examine millions of documents and has already taken statements from many key players.
Today Lord Hardie announced oral hearings would get under way on September 5.
The hearings are expected to take place on Tuesdays, Wednesdays and Thursdays each week until all evidence is heard, which the inquiry says is likely to be “several months”.
Witnesses will be cited to appear and the inquiry’s “core participants” - including the council and the key contractors - may undertake limited cross examination with Lord Hardie’s consent.
The inquiry has been tasked to investigate why the tram project incurred delays, cost more than originally budgeted and delivered significantly less than planned.
The hearings will take place at the inquiry’s offices at Waverley Gate, Waterloo Place and will be open to members of the public and interested organisations but seating capacity is limited to 50 and will be available on a first come, first served basis.
Lord Hardie said: “Today’s announcement marks a milestone in the Inquiry’s ongoing progress. The oral hearings form an essential part of the important work of the Inquiry and the evidence heard will play a crucial role in informing my final recommendations.
“In advance of these hearings, a significant amount of activity has already taken place including identifying, retrieving and reviewing more than six million documents and the ongoing gathering of statements from a significant number of witnesses.
“The hearings are just one of a number of steps the Inquiry is taking to provide robust recommendations to ensure future major tram and light rail infrastructure projects of a similar nature to the Edinburgh Trams avoid the problems this project experienced.”