Supplemental Environmental Impact Statement/Environmental Impact Report

Draft Supplemental Environmental Impact Statement/
Environmental Impact Report Refinements

The Federal Transit Administration (FTA), in cooperation with the Federal Railroad Administration and the Transbay Joint Powers Authority (TJPA), has prepared a Draft Supplemental Environmental Impact Statement/Environmental Impact Report (SEIS/EIR) to evaluate refinements to the Downtown Rail Extension (DTX) component of the Transbay Program, as well as other transportation improvements and development opportunities associated with the Transbay Program. The SEIS/EIR supplements and updates an earlier report certified by the TJPA in 2004 and adopted by the FTA in 2005.

The components evaluated in the Draft SEIS/EIR are shown below:

  1. Train Box Extension – The underground train box could be extended east one block to Main Street.
  2. Intercity Bus Facility – A new bus facility would be constructed above the extended train box between Beale and Main streets. It would serve operators such as Amtrak and Greyhound.
  3. Ventilation and Emergency Egress Structures
    Six emergency ventilation/evacuation structures would be co-located with emergency tunnel exits at various locations along the DTX alignment.
  4. Taxi Staging Areas – Curbside passenger loading and unloading spaces for taxis would be provided on Natoma Street alongside the new intercity bus facility.
  5. BART/Muni Underground Pedestrian Connector
    A pedestrian connection would link the Embarcadero BART/Muni Metro Station to the Transit Center.
  6. Bicycle/Controlled Vehicle Ramp – A bicycle ramp would lead to below-grade bicycle facilities within the Transit Center. A separate controlled-access vehicle ramp to the Lower Concourse (for use by emergency and approved maintenance vehicles) would run parallel to the bicycle ramp.
  7. Widened Throat Structure – The proposed widened throat structure provides the connection between the underground tracks and the train box below the Transit Center. It will conform to design specifications required for high-speed rail service.
  8. Rock Dowels – Rock dowels are approximately 15-foot-long rods that would be installed along the mined tunnel segment.
  9. Parking at AC Transit Bus Storage Facility – The AC Transit bus storage facility would be used for off-hours/nighttime or special event parking when not in use by AC Transit for regular operations.
  10. Fourth and Townsend Underground Station Realignment – The underground station would be realigned to parallel Townsend Street.
  11. Tunnel Stub Box – A new below-grade train box at the west end of the Caltrain railyard near Townsend and Seventh streets would be constructed to accommodate future grade separations and expedite future arrival of below-grade Caltrain and high-speed trains.
  12. Additional Trackwork – A turnback track and maintenance of way storage track would be constructed within the existing Caltrain right-of-way between Hooper Street and Mariposa Street, immediately east of Seventh Street.