Oakland Wye
The Oakland Wye is an underground flying wye junction in downtown Oakland, California which serves the Bay Area Rapid Transit system. Trains can switch between the northbound Richmond or Antioch lines, the westbound San Francisco lines, and the southbound Berryessa or Dublin/Pleasanton lines. The Oakland Wye is the center of the BART system, and is a bottleneck for the whole system because every regularly scheduled BART train passes through it.
Design
The wye is a flying junction that is approximately centered underneath Broadway and 9th Streets. Trains coming from the underground station approach the wye from underneath Broadway and those from the underground station approach from approximately underneath 9th Street. Those trains coming from the elevated station enter tunnel portals near Washington and 5th Streets before turning towards Broadway. An additional third track provides additional capacity between West Oakland and 12th Street, and is normally used by -bound trains. Emergency exit/access points are located in a small building at 7th & Broadway with access to the A and M lines and a sidewalk hatch at 9th & Harrison with access to the A and C lines.The original operating speed through most of the Oakland Wye was intended to be. Design problems led BART operations to impose a lower speed limit on most tracks. Although the design has since been corrected, the speed restrictions remain as a cautionary measure. The center "CX" track connecting West Oakland station to 12th Street is the only track with a higher operating speed of through the Wye.
History
Construction
Early plans called for the Wye to be centered underneath Broadway and 8th Street, but this was later changed to Broadway and 9th. This required a tighter turn between Lake Merritt station and 12th Street/Oakland City Center and, consequently, lower speeds through the Wye. There is some evidence that then-Oakland mayor John C. Houlihan objected to the original 8th Street location because it threatened a store owned by a friend of his.A third track connecting West Oakland, 12th Street Oakland City Center,, and stations was completed in 1986. Originally the MX/CX was used for peak hour service. Since 1992, it has been used almost entirely for eastbound Yellow Line trains, allowing for cross-platform transfers with Orange Line trains.
Incidents
On December 17, 1992, a southbound train split a switch at the north end of the wye, injuring 14 passengers.In February 2000, automatic train controls failed due to a loose cable and trains through the Oakland Wye were forced to operate in manual and slow to when switching tracks.
In February 2009, two northbound trains from West Oakland and Lake Merritt collided and partially derailed in the Wye while merging to approach 12th Street/Oakland City Center.