After 20 years of planning and eight years of construction, Caltrain’s initiative to transition the rail corridor between San Francisco and San Jose from diesel to electric service marks a pivotal moment. The transformational Peninsula Corridor Caltrain Electrification Project moves the San Francisco Peninsula toward modernized, faster, sustainable public transportation.

Caltrain debuted its cutting-edge, fully electrified service on the 51-mile corridor during the fall of 2024.

Greener rail for the Bay Area

More than 100 years after the opening of train passenger service in the area, Caltrain is introducing a new era on the corridor with electrification, which improves Caltrain system performance and curtails long-term environmental impacts by reducing noise, improving regional air quality and lowering greenhouse gas emissions.

The electric trains are more energy efficient and because they are powered by renewable energy, their carbon footprint is significantly lower than the locomotives previously used on the corridor.

“This project represents a leading-edge change that has gained attention locally, nationally and even internationally,” said Pranaya Shrestha, senior program manager for HNTB, which served as owner’s representative for the project. “A unique aspect of this corridor is that it’s a complete partnership. Caltrain garnered not only public support, but also support from the governor’s office and federal elected officials.”

Valley Transportation Authority in San Jose, the San Francisco Municipal Transportation Agency and the California High-Speed Rail Authority are among Caltrain’s project partners. The Federal Transit Administration and the state’s Transit and Intercity Rail Capital Program provided key funding for the project.

HNTB managed planning and communications between Bay Area stakeholders, meeting with city, county and state leaders to understand their expectations and ensure the effort stayed on track and on budget.

The project team took to heart the communities’ goals, including maintaining the historical aspects of seven depots on the Caltrain corridor that are listed on the National Register of Historic Places. Rather than putting in galvanized contact poles, for example, the team found paint that matched the stations – each of which is unique – and secured approval from the public and local authorities to paint the poles so they would blend in with their stations.

HNTB’s scope of work also included managing design, construction and risk and coordinating activation, system startup and vehicle procurement activities.

“This historic electrification project also requires a new approach to Caltrain’s operations and maintenance,” Shrestha said. “HNTB partnered with the Caltrain team throughout the life of the project to navigate punch lists, manuals, operation maintenance, training and record drawings. Caltrain is fully prepared to maintain the system well beyond the design life.”

Built for passenger safety, capacity and comfort

Consistent with Caltrain’s goals, the project team minimized inconvenience to corridor passengers throughout the last eight years of construction by keeping existing service in place and scheduling construction when it had as little impact on riders as possible, including during overnight hours and weekends.

Construction included locating underground utilities, testing soil conditions, upgrading and inspecting signal and communication equipment and pruning and removing trees. The project team installed foundations and 2,569 pre-engineered poles and strung more than 2.8 million feet of wire to support the overhead contact (OCS) that powers Caltrain’s fleet of 19 new, high-performing electric trains.

Additionally, 10 traction power facilities — electric power stations used to provide, distribute and regulate electricity to the OCS and electric trains — were installed on the corridor. With little impact to the system, the power upgrades will accommodate California High-Speed Rail trains when they are ready, allowing riders to step off a Caltrain vehicle and onto high-speed rail to travel further south.

As part of its signal system upgrade, Caltrain implemented wireless grade crossing technology that will improve warning time consistency. When wireless crossing is enabled, Caltrain’s positive train control (PTC)-equipped electric locomotives send messages to a controller to facilitate constant warning times at the crossing based on the train’s GPS position and speed.

The electrification of the line also delivers more frequent service for passengers, including during weekends. Caltrain’s seven-car electric trainsets maintain operating speeds up to 79 miles per hour, zipping between San Francisco and San Jose in less than an hour.

Service offerings are increased by 20%, with trains arriving every 15 to 20 minutes during rush hours at most stations and every 30 minutes during weekends, midday and evenings.

Each train car is equipped with 85 to 100 roomy seats, free Wi-Fi, electrical outlets under every fixed seat, onboard digital displays and expanded storage capacity. Two bike cars on every train provide space for 36 bicycles each. Each train includes an ADA-compliant restroom. CCTVs installed in the train cars enhance safety, and the electric trains provide a quieter, more comfortable rider experience.

Long-term benefits in and beyond the region

Within the Bay Area, Caltrain’s new electrified corridor will serve as a key component of the region’s interconnected transportation network. The Santa Clara Valley Transportation Authority (VTA) and Amtrak will connect with Caltrain at San Jose Diridon Station, while Bay Area Rapid Transit (BART) provides a direct link to San Francisco International Airport via Millbrae Station. California High-Speed Rail will eventually integrate with Caltrain, providing riders with improved access to destinations beyond the Bay Area.

“We are celebrating the completion of this project along with a transformative leap forward for our community and every rider who will benefit from these advancements,” said Michelle Bouchard, Caltrain executive director. “The electrification of Caltrain is a milestone we have been working toward for decades, and now everyone we serve can enjoy world-class rail travel. We are immensely grateful for our partners who have helped us deliver this project to ensure we can provide our community with safer, more efficient and sustainable transportation options.”

The electrification of Caltrain’s San Francisco-San Jose corridor is set to offer the region’s communities a more sustainable and efficient transportation solution, reshaping how the Bay Area moves for decades to come. Shrestha expects the project, completed on the oldest continuously operating railroad in the West, to also serve as a model for rail transit modernization throughout the country.

“It's important to note that this historic, 160-year-old corridor, now electrified, not only brings people and communities together today, but also will be used by our grandchildren and their grandchildren,” he said.