Background pictured above) since the early 1950s; they were replaced with electric train sets in the 2020s.|alt=An image of Caltrain's diesel locomotive, an EMD F40PH model. Commuter railroad service on the
San Francisco Peninsula was inaugurated in 1863 as the
San Francisco and San Jose Railroad and purchased by
Southern Pacific (SP) in 1870. SP announced that it would investigate the electrification of its line in September 1921, promising better and more frequent service. However, SP cited excessive post-war inflation, taxation, and competition from publicly funded highways as factors making electrification neither "practicable or desirable". In the early 1950s, SP began introducing diesel locomotives on the route. By 1977, Southern Pacific were facing rapidly declining ridership and petitioned the state
Public Utilities Commission to allow them to discontinue the commuter rail operation. From 1980 until 1992, the
California Department of Transportation (Caltrans) and the three service counties,
San Francisco,
San Mateo, and
Santa Clara, subsidized Southern Pacific operations on the railway until the local Peninsula Corridor Joint Powers Board (PCJPB) acquired the right-of-way in 1991.
Early electrification proposals In 1992, Caltrans released the first feasibility study detailing the possibility of electrifying the railroad between San Francisco and San Jose. The 1992
Feasibility Study proposed replacing the existing diesel-electric locomotives with either a fleet of
EMD AEM-7 electric locomotives to move the existing gallery passenger cars or
Metro North Budd M-2/M-4 EMUs. The primary benefits of an electrified railway would be improvements in air quality, noise, and acceleration, but would also save on other ancillary costs, such as lubricating oil, cooling water, maintenance, and refueling. Because of the relatively close spacing between stops, the improved acceleration using electric locomotives compared to the existing diesel-electric locomotives would cut transit time between San Francisco and San Jose by up to twelve minutes, and using EMUs would cut the time over the same distance by up to 23 minutes, assuming the use of ten-car trainsets. electric locomotive, part of the equipment proposed in the 1992
Feasibility Study to electrify Caltrain. This AEM-7 is in revenue service with
SEPTA.|alt=An image of an electric locomotive, an AEM-7 model, that was proposed in a 1992 study. Due to funding shortages, the project was postponed for the next two decades. In 1997, Mayor
Willie Brown canceled the appropriation for San Francisco's share of costs to extend rail service to downtown, saying Peninsula residents "ought to fund the whole project" since it would mainly benefit their commute. San Francisco instead applied the money to the
Third Street Light Rail Project.
Mike Nevin, PCJPB member from San Mateo County noted that while the downtown extension "would have enhanced particularly the electrification of the system", lack of it would not cause Caltrain to collapse. Instead, Caltrain studied a list of potential upgrades and went on to publish a draft
Rapid Rail Study on October 1, 1998, which prioritized capital improvements to the physical infrastructure with the overarching goal of expanding rail service. At that time, Caltrain was reporting daily ridership of approximately 25,000 passengers, a 40-year high. The study concluded that in order to meet the five goals presented in the
20-Year Strategic Plan of 1997, Caltrain should first rehabilitate and enhance the line, then electrify it. By itself, electrification was not projected to significantly improve service, and the high estimated cost of electrification and its lower priority meant electrification would be deferred. Some of the money to accomplish the rehabilitation and enhancement of existing track came from funds that had been intended for the downtown extension. Steve Schmidt, a councilman from
Menlo Park, argued that electrification instead should be the top priority to make the rail line more palatable to neighbors, citing improvements in noise and pollution. Other advocates for electrification of Caltrain noted the $1.2 billion
BART extension to
San Francisco International Airport may have revived the decades-old dream of
BART around the Bay, which would render an electrified Caltrain redundant. The electrification of Caltrain was assigned a higher priority than a future expansion of the system, which included proposals to bring service to
Union City across the
Dumbarton Rail Bridge as well as increased service to
Gilroy and
Salinas. Under the latest proposal to revive rail service over the
Dumbarton Rail Corridor, diesel multiple units would first be used to establish Dumbarton Rail service as a rail shuttle between a new rail station in
Newark and Caltrain's
Redwood City station, later extending service from Newark to
Union City, and finally followed by a commuter rail operation running from Union City to San Francisco and San Jose using EMUs. In 2003, The San Francisco County Transit Authority proposed Proposition K in San Francisco, a local transportation sales tax. Voters were given an expenditure plan estimating the total cost of Caltrain electrification as $183.5 Million with San Francisco's share costing $20.5M, met with Proposition K, which passed.
Caltrain/HSR blended system project includes funding for public transit systems along its route, including Caltrain.|alt=A map detailing California high-speed rail's "bookend projects", or projects at the tail end of high-speed rail route to improve public transportation and access to high-speed rail stations. Despite increasing ridership, Caltrain experienced a budget crisis in 2011 that nearly forced it to cut service to peak commute hours only, while funding sources for electrification remained unidentified. At the same time, the
California High-Speed Rail Authority (CHSRA) was having trouble identifying a route from San Jose to San Francisco in the face of local opposition. In response, U.S. Representative
Anna Eshoo, State Senator
Joe Simitian, and Assemblymember
Rich Gordon announced a "blended" plan to partially fund electrification with high-speed rail money in return for allowing high-speed rail trains to share tracks in the future. Later, Caltrain announced that it had studied the plan and believed it to be feasible. Under a proposed agreement between Caltrain and the CHSRA, details of which were leaked in February 2012, up to $1 billion could be available from the high-speed rail project to help fund the CalMod project, including the
positive train control system (dubbed "CBOSS"), electrification of the infrastructure, and elimination of some grade crossings. Under the agreement, the Peninsula Corridor would become eligible for high-speed rail money because the planned routing to San Francisco would use the same lines. This was one of two investments in "bookend" electrification projects, which were intended to upgrade existing passenger rail services near the planned CHSRA San Francisco and Los Angeles terminals to allow high-speed rail to share infrastructure. which received approval from the
Metropolitan Transportation Commission a week later. Under the memorandum, $706 million from the high-speed rail bond would be matched by state, regional, and local transportation funds to pay for the estimated $1.5 billion needed for CalMod. In September 2012, the
California Transportation Commission released $39.8 million to modernize CBOSS. A month later, the expected funding from high-speed rail bonds rose to $1.5 billion, which alongside electrification provided funding for the planned Downtown Extension (DTX), which would move the northern terminus of the Caltrain line from 4th and King to the
Salesforce Transit Center. CHSRA approved the issue of bonds in December 2016. Critics of high-speed rail felt the slower trips and reduced service caused by "blending" the two systems over the Peninsula Corridor did not meet the original voter-approved vision of a quad-track line between San Francisco and Los Angeles, and ridership would never meet projections.
Lawsuits . The town of
Atherton has backed litigation against Caltrain's electrification plans.|alt=An image of a train station, including tracks, platforms, and a shelter. The town of
Atherton, which lies on the tracks, was an early and vocal opponent of electrification. Residents opposed electrification and the proposed high-speed rail route because the overhead electrical lines would require tree removal and the town could potentially be divided in two by permanently closing the two grade crossings at Fair Oaks Lane and Watkins Avenue. In February 2015, shortly after the project received environmental clearance from the state, Atherton sued Caltrain, alleging the agency's environmental impact review was inadequate and that its collaboration with the CHSRA should be further vetted. In July 2015, the suit proceeded after Caltrain's request to the
Surface Transportation Board to exempt it from
California Environmental Quality Act (CEQA) guidelines was denied. Atherton reiterated its opposition to electrification on the basis that overhead wires would require removing a significant number of heritage trees, and city representatives asserted that "newer, cleaner, more efficient diesel trains" should supplant plans for "century-old catenary electrical line technology". Atherton mayor Rick De Golia was quoted as saying "Caltrain is locked into an old technology and 20th century thinking". After Caltrain issued infrastructure and rolling stock contracts in July 2016, Atherton representatives did not file a temporary restraining order to halt those contracts, preferring to let the suit proceed to a hearing. In September 2016,
Contra Costa County Superior Court Judge
Barry Goode sided with Caltrain, ruling that the electrification project did not hinge on the high-speed rail project's success, and was thus independent from the latter. Atherton sued CHSRA again in December 2016, stating that using bond money intended for high-speed rail for CalMod was a material change in usage and therefore was unconstitutional because such a change would require voter approval first. Mullin noted "this entire Caltrain corridor is the epicenter of the innovation economy and it's a job creation and economic engine. This electrification project, I would argue, is monumental with regard to dealing with [increased traffic and environmental impacts] effectively and efficiently." Parsons began physical work on CBOSS in September 2013, starting with the installation of a fiber optic line along the Caltrain right-of-way. The Federal Railroad Administration (FRA) approved Caltrain's plans in 2014 and Caltrain noted that CBOSS was due to enter revenue service by the end of 2015. Because Caltrain had multiple goals for CBOSS, including increased safety, improved operational efficiency, and ensured interoperability with other rail providers (Caltrain shares tracks with Union Pacific,
Altamont Corridor Express, and Amtrak), The Peninsula Corridor Electrification Project (PCEP) draft environmental impact report was released in February 2014. After addressing comments received, PCJPB certified the final environmental impact report in January 2015. A pre-qualification survey was sent out in May 2014, and six firms were pre-qualified to bid on PCEP construction, which was eventually awarded to
Balfour Beatty Construction. In July 2016, Caltrain's Board of Directors awarded contracts to Balfour Beatty and
Stadler Rail to construct infrastructure for the electric trains and the electric trains themselves, respectively. Balfour Beatty was awarded a $697 million contract, its largest contract in the United States, to electrify the line at 25 kV AC, replace signaling systems, construct two
traction power substations, one switching substation, and seven paralleling substations. The Swiss firm Stadler was awarded a $551 million contract to deliver 96 of their "
KISS"
bilevel electric multiple unit cars, formed into 16 six-car trains. Under the contract, Caltrain holds an option to increase the order with an additional 96 cars in the future. The contract also marks the first American design win for the Stadler KISS. The first trains are scheduled for delivery in August 2019. In April 2016, after missing the initial October 2015 deadline, Caltrain requested a third party review of the CBOSS project from the
American Public Transportation Association (APTA). APTA noted that Caltrain was not effectively managing the project schedule and cost because of generally poor communication between Caltrain's project management and Parsons, and Caltrain's project manager did not have the technical experience or authority to resolve technical and contractual issues with Parsons. In February 2017, Caltrain terminated its contract with Parsons for failure to perform on time and budget and announced potential litigation. Parsons filed suit on February 22, saying delays were due to changing client requirements and circumstances beyond their control. Caltrain filed suit a week later, seeking $98 million in damages; although the system has been mostly installed, testing is still incomplete. The plan to complete the installation of positive train control (PTC) was presented to PCJPB in early 2018. At the March 1, 2018 meeting, the PCJPB awarded the $49.5 million contract to complete PTC to
Wabtec. The switch to Wabtec implements I-ETMS technology, which was evaluated to be "the only technically and financially viable" solution to completing PTC before the FRA's deadline of December 31, 2018. Approximately 80% of the equipment for CBOSS that had already been installed was able to be reused, and FRA approved a revised schedule in January 2019 to implement PTC by December 2020. By February 2017, the electrification project had secured $1.3 billion in state, local, and regional funding, with the remaining funding gap to be closed by a $647 million grant from the FTA's Core Capacity program. The grant had undergone a two-year review process starting in November 2015 under the
Obama Administration and received a "medium-high" rating from the FTA in August 2016, However, during the review period, the fourteen
Republican party U.S. House representatives from California sent a letter to Secretary Chao, urging her to deny funding due to the project's ties with high-speed rail, which they opposed. The letter went on to call the project "an irresponsible use of taxpayer dollars". The
Sacramento Bee pointed out that despite regularly soliciting campaign funds from Silicon Valley business leaders, Representative and House Majority Leader
Kevin McCarthy, the author of the Republican letter to Secretary Chao, was targeting a project that benefited the region directly. Another Republican signatory, Representative
Devin Nunes, was unmoved by arguments on infrastructure benefits, saying in late February that he would not "feel too bad about one of the richest places on the planet not having a train." Fellow Republican Representative
Jeff Denham defended the letter, saying Caltrain's electrification project and CHSRA were closely intertwined because the former derived some funding under the "blended plan" agreement. Representative
Tom McClintock reiterated his opposition to high-speed rail without addressing Caltrain: "I have never supported a dollar of state funding going for [high-speed rail], and would never support a dollar of federal funding". Representative
Mimi Walters also made a statement that she was not opposed to electrification, but instead held "serious concerns about the use of taxpayer funds for a project that is tied to high speed rail". The Democratic letter went on to note the infrastructure benefits of the project and the creation of 9,600 jobs, including 550 jobs at a new Stadler USA plant in Salt Lake City. In the end, Secretary Chao heeded the Republican letter's arguments, and deferred the grant in a letter written by FTA Executive Director Matthew Welbes to Caltrain which stated the FTA needed "additional time to complete review of this significant commitment of Federal resources". Caltrain had expected Secretary Chao to approve the grant and sign the grant agreement by March 1, which is normally a
pro forma step performed after the thirty-day comment period for a highly rated project, and had already awarded construction contracts.
Balfour Beatty Construction and
Stadler Rail had already begun preparations to upgrade the existing tracks and build electrical trainsets, respectively. Caltrain negotiated an emergency four-month contract extension at a potential cost of $20 million. Under the preliminary budget proposal released in mid-March 2017, the
United States Department of Transportation's Capital Investment Grant Program would be eliminated, although approved projects would continue to be funded. the
East Bay Times, a noted CHSRA detractor, and
The New York Times, which called the delay "counter to Mr. Trump's campaign promises of increased infrastructure spending." Henry Grabar noted the grant deferral could be "an early test of a simmering fear that the state's outspoken political opposition to the Trump administration might come with a price". San Jose Mayor
Sam Liccardo met with Department of Transportation officials, urging them to upgrade a system that "was built under the presidency of
Abraham Lincoln". Additionally, more than 120 Silicon Valley business leaders sent a letter to Secretary Chao, asking her to explain "the last-minute attempt to derail two decades of work". and subsequently met with Secretary Chao and Representative McCarthy, urging them to reconsider the funding deferral, saying afterward that he was "cautiously optimistic" that the money would be released. On April 30, legislators in the U.S. Congress released the proposed 2017 federal budget, which included partial funding for the electrification project, but restricts its distribution unless Secretary Chao signs off on the grant. The proposed budget includes $100 million of the $647 million grant, with the balance expected in future years. Secretary Chao claimed she could not sign the grant without the full grant being budgeted, which was disputed by Caltrain and both California Senators
Dianne Feinstein and
Kamala Harris. On May 22, the FTA announced its intent to sign the funding grant, restoring the final piece of funding for the electrification project. The official grant was finally signed on May 23.
Construction and testing A new weekday schedule designed to allow time for construction became effective on April 10, 2017. The weekend schedule was revised on July 15, 2017, which decreased frequency from 60 minutes to 90 minutes between trains and eliminated eight trains per weekend day. , Cal. Sen.
Scott Wiener, San Francisco Mayor
Ed Lee, Gov.
Jerry Brown, and Rep.
Nancy Pelosi at the July 21, 2017 groundbreaking ceremony An official groundbreaking ceremony was held on July 21, 2017, at the
Millbrae station. , 149 poles had been erected in San Bruno and South San Francisco. In December 2018, Caltrain was carrying 65,000 passengers a day, and expected to carry four times that amount by 2040. Accordingly, Caltrain announced plans to increase its electric train order by a third. After funding was received from the California State Transportation Agency's Transit and Intercity Rail Capital Program, Caltrain's board unanimously approved the purchase of additional cars from
Stadler to increase the fleet from 16 six-car sets to 19 seven-car sets. Balfour Beatty reported in 2019 the completion of construction could be delayed to April 2022 in a report to the
San Francisco County Transportation Authority (SFCTA); the projected 12-month delay was blamed on the unexpected presence of underground utilities. In June 2021, Caltrain announced that electric service would be delayed to late 2024 due to supply chain disruptions during the
COVID-19 pandemic, issues with the signal system, and "unforeseen conditions under Caltrain's tracks". In February 2022, the last foundation required for the new overhead catenary system was completed, with the entire line planned to be energised by summer 2022. Testing of the line would then begin using an
AEM-7 electric locomotive, with revenue service planned for 2024. To expedite construction, the weekday train schedule was reduced and fewer stops were planned north of Hillsdale temporarily in the second half of March 2022. However, construction was suspended temporarily that month after a southbound train collided with work equipment at milepost 11.6 in San Bruno on Thursday, March 10. The train came to rest near San Felipe Avenue, and spilled fuel caused a fire, which damaged the tracks, locomotive, and passenger car. The work crew had contacted the train dispatcher at 9:50 a.m. (local) to establish exclusive occupancy on track 2 for the three hi-rail work vehicles, then released the exclusive occupancy at 9:58; the collision occurred at 10:33. According to the locomotive's event data recorder, the last recorded speed of the southbound train was , but the engineer had pulled the emergency brake upon sighting the work vehicles. The reduced schedule was implemented again starting in May to accommodate construction activities in San Mateo and Burlingame. Clearance testing of the first electric trainset on the Caltrain corridor began in July 2022. The southern Traction Power Substation was energized that August. Initial testing of the overhead catenary system and trains began along the Santa Clara Drill Track in June 2023, between the Santa Clara and College Park stations. The electrification of the line was completed in April 2024. Caltrain Board Chair Dev Davis, Governor
Gavin Newsom,
Federal Railroad Administration chair
Amit Bose, U.S. Senator
Alex Padilla, U.S. Representatives
Nancy Pelosi,
Kevin Mullin and
Anna Eshoo,
California State Transportation Agency chief Toks Omishakin, noted transit advocates and state legislators
Phil Ting and
Scott Wiener, and the mayors of San Francisco and San Jose,
London Breed and
Matt Mahan, respectively, were among the passengers. Revenue service began the next day, and was scheduled to ramp up to its highest frequency by September 21. On that date, Caltrain held a celebration to mark the launch of the new schedule, and offered free rides throughout the day. Trip times were shortened thanks to the faster acceleration of the new electric multiple-unit trains. A scheduled local train trip from San Jose Tamien to San Francisco 4th and King was shortened from 115 minutes with a diesel train to 83 minutes with electric service, an improvement of 32 minutes. Electric express trains improved trip times despite adding more stops - a 7-stop diesel express train from San Jose Diridon to San Francisco 4th and King was scheduled at 66 minutes, while a 10-stop electric express train went down to 59 minutes despite making more stops.
Environmental effects Replacing the diesel locomotives with electric multiple units was expected to reduce air pollution and noise. A
UC Berkeley study conducted in 2024, before and after complete electrification of San Francisco to San Jose service, found substantial reduction in black carbon particulates, a major component of
diesel exhaust. Black carbon measurements onboard trains fell by an average of 89% after electrification. The study estimated that this reduction in diesel particulate exposure would reduce excess cancer risk by 51 cases per million people among daily train commuters, and 330 cases per million people among train conductors. Ambient black carbon particulate measurements at the station platform and concourse at
4th and King station fell significantly, by as much as 1.9 micrograms per cubic meter - reductions equivalent in magnitude to what took three decades of environmental intervention to achieve in California at the end of the 20th century. The reduced air pollution is expected to improve the health of
El Palo Alto, a coastal redwood tree and historical landmark which stands about away from the Caltrain tracks and lends its name to
Palo Alto. Coal soot and
diesel exhaust are presumed to have killed parts of the tree's crown since the 19th century. The lack of exhaust emissions will benefit air quality throughout the railway corridor, and the new units are significantly quieter than the previous stock. However, the lower noise levels have resulted in Caltrain warning the public to take extra care at crossings. The new electric trains are more efficient than originally expected. Electricity costs were originally expected at $19.5 million per year, but were revised down to $16.5 million after several months of service, and later to $15.3 million. After $6 million in state energy credits, the first year of electric service will have lower costs than the previous diesel service. Approximately 23% of the electricity consumed by trains is recaptured and returned to the grid thanks to
regenerative braking. Caltrain was originally not compensated for energy returned to the grid, but successful negotiations with utilities in October 2025 results in an estimated $1 million per year compensation for returned energy. ==Funding==