The MBTA isn’t the only transit agency whose new trains will be made in Massachusetts.

Officials with Philadelphia’s transit system this week awarded a $137.5 million contract for 45 new commuter rail trains to China Railroad Rolling Stock Corp., the Chinese government-owned rail firm that is building new subway trains for the T at a Springfield factory.

That follows CRRC’s win in December of the bidding to build new subway cars for Los Angeles’s transit system. Assembly work for both jobs will be done in Springfield.

CRRC is a massive company formed by the merger of two Chinese rail manufacturers, with operations around the world. But until the fall of 2014, when it was contracted for $566 million to build new Red and Orange line trains for the MBTA, it had not done any business in North America.

The company underbid other competitors for the MBTA contract by hundreds of millions of dollars, and as part of the arrangement agreed to build the $95 million Springfield factory that is expected to employ 150.

That deal has become a springboard for CRRC to pick up business across the country. In addition to the Philadelphia and Los Angels jobs, it will also build new trains for Chicago — though those will be made in a new Illinois factory. Last year, it secured another contract worth $277 million with the MBTA to expand its work to include the entire Red Line fleet.

Its US expansion has not been without controversy. When the Patrick administration selected the company for the MBTA job, opponents decried the human rights record of its owner, the Chinese government.

CRRC has also been criticized for undercutting prices by its competitors and some members of Congress, who last summer in a letter to the US Treasury accused the company of using the Chinese government to subsidize its prices. CRRC has been the low bidder in all four of the US cities where it has won contracts. Lydia Rivera, a spokeswoman for CRRC, said the company offers low prices because of its global footprint and existing supply chains.

The growth is good news to Springfield Mayor Domenic Sarno. The factory broke ground in 2015 and is expected to begin delivering vehicles for the MBTA next year. Generating business from other transit agencies was always part of the plan, Sarno said.

“This does not surprise me at all,’’ Sarno said. “I’m confident that they’re going to be receiving even more contracts.’’

Sarno speculated that the factory could be in line for more work if the federal government advances a stated goal of President Trump.

“They’ll continue to get orders,’’ he said. “The new administration, they want to do a massive infrastructure plan. ... It comes at an opportune time.’’

In April, about 30 employees at the Springfield factory are traveling to China for three months for orientation and training. The new MBTA vehicles are expected to begin assembly next year.

Adam Vaccaro can be reached at adam.vaccaro@globe.com. Follow him on Twitter at @adamtvaccaro.