Passenger Commuter & Regional Southern California hydrogen trainset to make revenue debut Saturday

Southern California hydrogen trainset to make revenue debut Saturday

By Trains Staff | September 12, 2025

Stadler-built train begins operation in San Bernardino County’s Arrow service

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Blue and white multiple-unit passenger train
San Bernardino County’s hydrogen-powered commuter trainset will make its revenue debut on Saturday, Sept. 13. Stadler

SAN BERNARDINO, Calif. — The first hydrogen-powered passenger trainset in the U.S. will enter revenue service this Saturday, Sept. 13, the San Bernardino County Transportation Authority has announced.

The train will debut on the 9-mile, five station Arrow corridor between San Bernardino and Redlands, Calif., and on its first day will offer zero-fare rides. The Redlands Daily Facts reports it is scheduled to make its first departure from San Bernardino at 10:32 a.m.; the Arrow schedule is available here.

The Zero-Emission Multiple Unit, or ZEMU, trainset is a hydrogen fuel-cell version of Swiss manufacturer Stadler’s FLIRT (Fast Light Innovative Regional Train), also known by the manufacturer as the FLIRT H2. The trainset debuted at InnoTrans in Berlin in 2022 [see “Stadler unveils first …,” Trains.com, Sept. 21,2022]. It arrived in Southern California in June 2024 after extensive testing in Europe and at the Transportation Technology Center in Pueblo, Colo. [see “Hydrogen trainset arrives …,” Trains.com, June 2024]. It has been undergoing further testing in San Bernardino County since then.

“Saturday will mark a historic day for SBCTA,” Rick Denison, the Authority’s board president, said in a press release. “ZEMU is proof of our commitment to improving regional air quality, embracing innovation, and expanding clean-air transit options throughout the county. I look forward to riding ZEMU and am excited for residents and visitors to experience this train firsthand.”

5 thoughts on “Southern California hydrogen trainset to make revenue debut Saturday

  1. The real question is where do you get your hydrogen? If there was an existing vast supply we would be burning it now like natural gas. If there is some involved and expensive prosses to get it then it all starts to fall apart.

    1. Hydrogen is typically made by passing an electric current through water to separate the hydrogen and oxygen. Later, the fuel cell combines hydrogen and oxygen to get back water and electricity. Essentially, the hydrogen is a way to store the energy in electricity and get it back later. It is an alternative to a battery, possibly with a longer range. It is not a source of energy. It is green if, and only if, the electricity used to produce it was generated by a clean source.

  2. Curious as to where the hydrogen refueling equipment is located. Presumably at one of the end points of the run. Is the hydrogen liquid or a gas? Are the fuel cells easily replaceable if they fail? How many miles can a full refueling provide?

    1. Range-wise, this same set last year set a world record (for hydrogen trains) by traveling over 1,700 miles at the test center in Pueblo without refueling. It took 46 hours. I wouldn’t expect that distance in regular service, but it seems fair to say that one “tank” will easily last a day’s commuter service. I would assume the refueling equipment is at the main maintenance yard on the San Bernardino end. I can’t answer the other two questions.

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