BART’s sleek new railcars finally passed safety tests over the weekend — months behind schedule — and are on track to start carrying commuters around Thanksgiving, transit officials said Monday.

John Garnham, project manager for BART’s new fleet, said the first 10 new cars, which have undergone rigorous testing and subsequent fixes for the past year and a half, completed the last of a lengthy checklist of tests and requirements on Saturday.

BART and railcar manufacturer Bombardier are now working their way through 3,000 documents they need to submit to the California Public Utilities Commission to prove the cars are ready for passenger service. The plan is to submit the paperwork to the commission next Monday, starting a review process expected to take 21 days.

“We’re ready to go,” said Garnham. “It’s just a matter of getting the approvals, getting everything lined up.”

Garnham said he doesn’t expect any surprises from the PUC, which has observed testing since the first new trains arrived at BART’s Hayward yard early in 2016.

Once BART gains approval for the new railcars, it will press them into regular service, probably running them as a single 10-car train during its morning and evening peaks and two five-car trains during the system’s less-crowded hours.

Since BART runs about 62 trains during its busiest morning and afternoon hours, commuters’ chances of encountering the few trains consisting of new cars are relatively remote.

It will be well into 2018 before most BART passengers get a chance to ride on the bright new railcars, which feature three doors on each side, bike racks, brightly colored green and blue seats and more reliable heating and air conditioning.

Bombardier has already cranked up the production line at its assembly plant in Plattsburgh, N.Y., and expects to deliver another 10 cars by the end of the year. Within a few months, the manufacturer should be building 16 new cars a month and shipping them by truck to the Bay Area. They will undergo two to four weeks of tests and inspections then be rolled out into service.

“Sometime by May or June, you’ll probably have a good shot at riding one,” said Garnham, who expects to have 70 new cars on the tracks by then.

No specific schedule has been set for where and when the new trains will operate, Garnham said, but the idea is to move them around the system to give more operators a chance to get familiar with them, and more customers the opportunity to ride them.

Delays occurred when Bombardier delivered the first cars five months late and were exacerbated when testing revealed problems.

BART’s initial testing took place at its Hayward yard then moved onto the tracks in the early-morning hours after regular service shut down. For the past few months, trains made up of the new cars have run during regular service hours, though the only passengers they’ve carried were BART employees involved in testing or training.

The transit system expected the first batch of 10 cars to have problems, so it subjected them to extensive testing, designed to reveal the flaws, which Bombardier repaired. A variety of problems surfaced, ranging from mechanical trouble with friction brakes, and glitches with the lights, air conditioning, heating system and propulsion.

Those problems have been solved, Garnham said. Though he doesn’t anticipate any major problems with the new cars, he knows some will surface. The cars are under a two-year warranty, he said, and BART mechanics have been trained to fix and maintain the new cars.

For passengers, the wait for a better BART ride is coming to an end, he said.

“They’ll be very happy,” he said, the cars are “just a nicer ride.”

Michael Cabanatuan is a San Francisco Chronicle staff writer. Email: mcabanatuan@sfchronicle.com

Twitter: @ctuan