With a gentle bump and some cautious applause, Canberra's light rail finally left the station.

No sooner had the first vehicle left Gungahlin Place just before midday on Thursday, a baby burst into tears. The passengers didn't seem to mind. They weren't bothered being packed like sardines into the red vehicle's shiny red carriages.

This was history; Canberra history. And they were part of it.

Winners of a public ballot joined school children, ACT government representatives and the media on a special "preview" loop of the Civic to Gungahlin route, ahead of light rail's official launch on Saturday.

Megan Whittle was there with her children Maeve and Quinn, who will have to be told in years to come about the day they first rode Canberra's light rail.

"Excitement has been building for a while," Ms Whittle said. "We went to Melbourne last year and the tram was a huge highlight of the trip, so we wanted to make sure we were the first here."

Part of history, too, are the Canberra teenagers - Hejha Piran, Rafi Sagara, Naomi Abakah and Caterina Fellows - whose voices passengers will hear as the vehicles approach the 12 stops between Civic and Gungahlin.

"I'm actually really glad and really happy that this happened to us," Naomi told The Canberra Times, before she boarded the vehicle for the first time.

As the light rail left Gungahlin in its wake, passengers remarked at how the vehicle moved smoothly and quietly.

Transport Minister Meegan Fitzharris shpwed a mix of relief and excitement, less than 24 hours after the light rail was given the final approval.

The launch date had been a long time coming, she remarked, but it had arrived very quickly, too.

When he's older, Tommy Connolly will go to school at Dickson's Daramalan College, a stone's throw from a number of light rail stops.

"It fast, and it will mean there are less cars on the road, which will make it easier to get around and into the city," Tommy said.

The first voyage of the light rail was new and fresh.

But there was room for nostalgia on board.

Sheilah Barrie, 101, was there with her son and a book full of photos of her late husband, Dave Barrie.

Mr Barrie used to drive buses around Canberra, and is pictured in one of the photos standing outside the Kingston depot in the late 1930s.

"He would sure like this," Mrs Barrie said. "He'd probably like to drive it, too."

Born in Sydney, Mrs Barrie said she moved to Canberra in 1925. When she lived in Reid, the now inner-city suburb was nothing but bushland.

"It's amazing how much the city has changed. It is wonderful."

Canberra isn't the same city it was in 1925. It isn't the same city it was on Wednesday.

Chief Minister Andrew Barr said as much when he unveiled a commemorative plaque at the Alinga Street terminal on Thursday afternoon.

"This is the moment that Canberra grows up," Mr Barr said. "It is [the moment] the city moves into its next phase of growth and development and it does so with a real public transport system. It is the largest transport infrastructure project every undertaken in the ACT."

Ms Fitzharris declared the light rail had been delivered under budget, while Mr Barr boasted the project had "gone incredibly smoothly".

The chief minister's claim is likely to be disputed, or at the very least contested, by the businesses and motorists who have faced disruption and frustration during the construction phase.

But Mr Barr is resolute. Canberra is now a leader, not a follower.

"People can legitimately ask what can other cities learn from our experience here?" he said on Thursday.

"We have done a lot of things exceptionally well. We looked at what had gone wrong with major infrastructure projects in other cities - and you don't have to look too far up to the Hume highway to see the pitfalls of not doing projects well."

The proof of the light rail's success, or failure, will come when the vehicle doors open to the wider Canberra community.

The government is expecting 30,000 people to ride the light rail on Saturday.

There might yet be more, who knows?

History doesn't roll by every day.

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