RAILWAY AGE DECEMBER 2025 ISSUE: Newly electrified, Caltrain is operating 104 trains per day with one million monthly riders.
Jan. 16, 1864, marked the first day for passenger rail service between San Francisco and San Jose. Who knew that 160 years later, on Sept. 21, 2024, Caltrain would be operating electric trains along that same route?
“Now that we’re electrified, we’ve seen our ridership and our service increase with 104 trains a day, half-hourly weekend service,” said Brent Tietjen, External Affairs Manager for Caltrain.
Indeed, this past September marked the one-year anniversary of electric trains running on the corridor from San Francisco to San Jose. While Union Pacific still operates on parts on the segment and Caltrain’s diesel trains might run under certain circumstances, elsewhere Caltrain is “100% electric” and running on renewable power, according to Caltrain Public Information Officer Dan Lieberman.
The new Stadler US-built electric multiple-unit (EMU) trainsets offer amenities welcoming to the weary commuter, such as free Wi-Fi, power outlets at every seat and onboard displays with digital trip information. But strong weekend travel is what has given Caltrain a boost in its ridership. Monthly ridership broke one million in September for the fourth consecutive month; for fiscal year 2025, which ended June 30, ridership was up 47% over the previous fiscal year.
Weekend travel “is higher than it has ever been in Caltrain history,” as riders take advantage of a new offering of half-hourly weekend service, Lieberman said. “It’s just making it really easy to get around.” Caltrain also serves seven major league sports teams, tying with the New York Metropolitan Transportation Authority for having those connections.
Easing Into Electric
Groundbreaking for infrastructure improvements to allow electric trains to run began in 2017, but the design feedback process ran from 2016 to 2019. The manufacturing and testing phase took place from 2020 to 2024.
Getting the political will to provide funding was “a major lift,” Lieberman said. Caltrain experienced smooth sailing after those first initial steps, although putting up hundreds of miles of AC catenary 20 feet above an active railroad was also a challenge, he said.
Caltrain purchased 23 seven-car bilevel KISS EMU trainsets (161 railcars) from Stadler US as part of the Caltrain Modernization Program, with options for 55 more. In addition to these, there is one four-car bilevel BEMU (battery-electric multiple-unit) for use between Tamien and Gilroy.
KISS is an acronym for “Komfortabler Innovativer Spurtstarker S-Bahn-Zug,” which translated from German means “comfortable, innovative, sprint-capable suburban train.” Each EMU has a power output of 7,000 kW (9,387 HP). “Although the Stadler bilevel EMUs are a proven product in Europe and have been in service overseas for several decades, these will be the first to be deployed in the U.S.,” Stadler said in September 2023. “Caltrain’s new Stadler trainsets will serve as the foundation for the first modern, electrified railroad in California.”
Stadler US built the trainsets at its facility in Salt Lake City, Utah. After construction, they underwent testing in Pueblo, Colo., at TTC Operated by ENSCO, where they were eventually certified by the Federal Railroad Administration for passenger service. Caltrain then began revenue service operations in August 2024. “We did a soft launch in August of 2024. Two trains out every week,” Tietjen said. “We were happy with how smooth that transition went.”
Since the EMUs began running, Caltrain has experienced significant fuel and emissions savings, according to Lieberman. “We’re actually paying less than we did for diesel fuel at the moment,” he said.
The trainsets’ regenerative braking system has been returning about 23% of the power they receive from the electric grid. In October, Caltrain announced that its two primary power providers, San Jose Clean Energy and Peninsula Clean Energy, will allow it to qualify for a net billing rate starting in April 2026. This means that Caltrain could receive approximately $1 million annually for the clean power it sends back to the grid.
This financial benefit came about because of California AB (Assembly Bill) 1372, which qualified regenerative braking from electric trains to be considered as a renewable electric generation facility.
Future Plans
Caltrain photo.
While the electrification of the San Francisco-San Jose line for commuter rail service is largely complete, Caltrain is still working to potentially electrify its network south of San Jose. Its purchase of the BEMU from Stadler US for the Gilroy spur used funding from the state of California, with the condition that Caltrain would lend the trainset to other corridors to experiment with electric power, according to Lieberman. “If we can help other localities decide to get these beautiful, modern trainsets, we’re very excited to help,” he said.
Stadler US in December 2024 signed an agreement with Caltrain to supply on-site technical support, maintenance management software implementation, full materials management for both preventive and corrective maintenance, and diagnostic assistance. The contract also allows both parties to opt-in the BEMU pilot train into this agreement, Stadler said.
Capital projects beyond electrification include plans to connect to downtown San Francisco via tunnel. According to the San Francisco County Transportation Authority, the downtown Portal project will extend Caltrain and future California High-Speed Rail service from the 4th and King rail yard to the Salesforce Transit Center. The project, expected to be completed sometime in the 2030s, includes construction of a new underground station at 4th and Townsend streets. The Transbay Joint Powers Authority is responsible for the project.
Caltrain is also working on safety issues related to grade crossings, including deploying artificial intelligence to prevent incidents, according to Tietjen.
“Electrification has completely transformed Caltrain,” Executive Director Michelle Bouchard said in September. “We’re delivering cleaner, faster, more frequent service, and riders are responding in record numbers. This first year has shown what’s possible when we invest in sustainable rail, and we’re only just getting started.”
