PITTSBURG — Beginning this fall, BART’s new train cars will all be Bay Area-made.

The company that makes the cars, Canada-based Bombardier Inc., is moving into a Hitachi-owned warehouse on Loveridge Drive in Pittsburg, company representatives said Friday. Bombardier is leasing 122,750 square feet of the facility, with Hitachi retaining about 67,000 square feet, said Kolette Simonton, Pittsburg’s assistant director of economic development. The company will start with around 50 new jobs at the Pittsburg plant in September, when crews are expected to begin work on BART’s cars, eventually ramping up to 115 employees within five years, she said.

The move is a boon for the East Bay city, said Assemblyman Jim Frazier, D-Discovery Bay, especially in an area where residents are more likely to leave town for work, making some of the longest and most grueling commutes in the Bay Area.

“Bringing jobs is a novel concept to East County,” he said. “Normally, we have to participate elsewhere in our workforce and go travel sometimes hours. So for this effort, to be able to place jobs in East Contra Costa County, I am so thankful.”

BART is in the process of replacing its 669 cars with 775 new ones, and it is negotiating an agreement that would add 425 more, bringing the total to 1,200. As of Friday, BART had received 84 new cars, 75 of which are already carrying passengers. The agency expects to have 160 on its property by February next year. The cars, which suffered delays in the early phases of design and testing, have since received rave reviews from customers, said BART General Manager Grace Crunican. They are quieter and more comfortable too, she said.

“They are much cooler and warmer when you want them to be cool or warm,” Crunican said. “I want to thank Bombardier for the great design.”

The move will allow Bombardier to free up space at its plant in Plattsburgh, New York, where the cars are currently built, for new and upcoming East Coast orders while moving some of its West Coast contracts to Pittsburg. It will also help reduce the carbon footprint of the electric trains, which travel on the back of oversized big rigs to reach BART’s test tracks in Hayward, said Elliot Lee Sander, president of the New York-based Bombardier Transportation of the Americas.

“What is now a 3,000-mile cross-country journey to the Bay Area will now be a much shorter 50 miles,” he said.

In addition to the BART cars, Bombardier has contracts to maintain the AirTrain system at San Francisco International Airport, the new commuter rail fleet for the Los Angeles area’s Metrolink service and the Coast and Sprinter train cars for the North County Transit District in San Diego. It’s also in the early stages of bringing a new, automated people mover to Los Angeles International Airport, Bombardier representatives said. All told, the company employs about 500 people in California, not counting the new Pittsburg jobs.

The Pittsburg plant helps Bombardier compete on projects that use federal funds, which come with a “Buy American” mandate to use a certain portion of U.S.-produced materials, company representatives said. The move was partly made possible thanks to a $1 million California Competes Tax Credit, which is for businesses expanding or relocating here, Sander said. But it’s also a homecoming of sorts for the company, he said. When BART overhauled its original fleet in the 1990s, it used the Pittsburg-based company AD-Tranz, which Bombardier later acquired, Sander said.

“We are proud to be contributing to the region’s rejuvenation of the rail car fleet,” he said, “running on one of the busiest rail systems in the United States — an iconic rail system.”