• Altamont Corridor Express (ACE)

    Courtesy of ACE

    The Altamont Corridor Express (also known as Altamont Commuter Express or ACE) provides commuter rail service between Stockton and San Jose.  ACE uses Bombardier bi-level trains with 110 volt AC outlets, a bike car, and restrooms in every car.  Bicycle lockers are provided at every station except Fremont.

    Route Map

    » Link to official ACE website

    » Link to ACE page at Transit Unlimited Wiki


    By the numbers

    • Route length: 85 miles
    • Daily ridership: ~ 2,500 passengers/day (2005)
    • Average passenger trip length: 48 miles (computed from NTD2004)
    • 10 rail stations in 3 counties: San Joaquin, Alameda, and Santa Clara.
    • 4 round trips on weekdays between Stockton and San Jose.

    Governing body

    ACE is managed by the San Joaquin Regional Rail Commission (SJRRC). They contract with Herzog Transit Services Inc. to operate the trains.


    • Yearly operating budget: ~$11 million (FY 2005-06)
    • Yearly capital budget: ~$32 million (FY 2005-06)

    Funding is provided by passenger fares, San Joaquin County Congestion Mitigation and Air Quality federal grant funds, and operating subsidies from the three member agencies, (San Joaquin Regional Transit District, Alameda Congestion Management Agency, and Santa Clara Valley Transportation Authority (VTA)).

    Alameda County Measure B, a half-cent Sales Tax helps fund 2.12% of ACE operation in Alameda County.  Capital funding for station improvements is the responsibility of the member agency in the county where the station is located.

    How to support funding for this service

    Ride ACE, and contact elected officials including board members of member agencies asking for more service.

    Proposed improvements

    Proposed improvements

    Most of the railroad that ACE runs on is owned by Union Pacific. See

    Q. What problems are encountered when a passenger rail train uses tracks owned by freight rail companies?

    There has been an increasing level of freight traffic in the San Joaquin Valley, through the Altamont Pass and Niles Canyon, and along the Coast Line in Alameda and Santa Clara Counties.  In addition to freight congestion, more frequent train service by both Caltrain and Amtrak’s Capitol Corridor has meant heavy train traffic along the line between Santa Clara and San Jose Diridon Stations.  This bottleneck sometimes delays ACE trains.

    Officials at ACE are looking at ways to speed up and add more service (ACEForward project), including measures such as…

    • Double tracking in key locations.
    • Reactivate the county owned track in the Niles Canyon (currently used by Niles Canyon Railway excursion trains) to permit usage by freight trains and free up capacity on the current track for passenger service.
    • A dedicated right-of-way for passenger trains, including tunnels through the Altamont Pass.
    • Extension to Modesto and Merced. SB1, a fuel tax program approved by the state legislature in 2007, would provide $400 million towards extension to Merced, which is the proposed terminus for high speed rail in Central Valley where HSR will turn west toward San Jose over the Pacheco Pass.
    • Extension to Sacramento on the UP track (different than the track used by Amtrak San Joaquin) and possibly beyond.
    • Direct transfer with BART in the Tri-Valley area, either with locomotive haul trains or diesel multiple units to connect with BART in Livermore (by extending BART to Isabel Ave), or at the existing Dublin/Pleasanton Station. BART is conducting a separate study of extending BART with DMU trains as an alternative.


    ACE Milestones

    • 1989: San Joaquin Council of Governments, Stockton Chamber of Commerce, and the Building Industry Association of the Delta begin developing a 20-year transportation plan. 1990: San Joaquin County Measure K half-cent sales tax for transportation passes.
    • 1995: County of San Joaquin forms a joint powers agreement that creates the San Joaquin Regional Rail Commission to implement the rail plan.
    • May 1997: Agreement between the San Joaquin Regional Rail Commission, Alameda Congestion Management Agency, and the Santa Clara Valley Transportation Authority to create the ACE Joint Powers Authority.
    • October 19, 1998: First day of ACE operations with 4 daily weekday trains — 2 westbound trains in the morning and 2 eastbound trains in the evening — operated by Herzog Transit Services, Inc. under contract with the San Joaquin Regional Rail Commission.
    • February 2000: ACE adds a morning turn-back train between San Jose and Fremont.
    • March 5, 2001: To alleviate overcrowding, ACE drops the turn-back train and adds a third round trip that departs Lathrop-Manteca later in the morning and returns in the evening, for a total of 3 westbound morning trains and 3 eastbound evening trains. It also begins stopping at the Santa Clara Caltrain station near downtown Santa Clara.
    • August 1, 2005: ACE suspends service at Santa Clara Caltrain station.
    • August 28, 2006: ACE adds a fourth round-trip between Stockton and San Jose, providing mid-day weekday service
    • November 2, 2009: ACE discontinues mid-day round-trip.
    • May 2012: ACE restores service at Santa Clara Caltrain station.
    • October 2012: ACE adds a fourth round-trip during peak hours.