奧克蘭三角線位於加州奧克蘭地下，是灣區捷運系統里的重要區間。列車可通過此三角線前往[1][2][3]:45–46[4]
- 北行-12街/奧克蘭市中心站（里奇蒙方向 或 匹茲堡/灣角方向）
- 西行-奧克蘭西站（三藩市方向）
- 南行-美麗湖站（弗雷蒙 或 都柏林/普萊森頓方向）
因為所有列車都會經過這裏，所以此三角線是灣區捷運系統裏最重要的區間之一，但也因為複雜的結構成為了全線速度的瓶頸。[4][5]
結構
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大部分軌道的設計速度是27英里每小時（43公里每小時）。由於設計失誤，控制中心規定的限速是18英里每小時（29公里每小時）。雖然失誤隨後被修正，基於安全考慮，這個限速依然不變。[4]唯一「高速」的通道是從奧克蘭西前往12街/奧克蘭市中心的軌道（圖中MX→CX），允許的速度達到36英里每小時（58公里每小時）。[4]
另外，MX軌道和M1軌道之間也有渡線，加上麥克阿瑟站附近繁多的岔道，在特殊情況下（如2018年金州勇士勝利遊行時），CX→MX→M1軌道也會被作為下行前往三藩市的通道，以提高通行的效率，同時北上的列車將只使用M2→C1軌道。
歷史
奧克蘭三角線曾多次發生事故，而由於其重要性，每次事故都會波及整個系統。有專家曾提出建立多個通道來降低三角線故障所帶來的影響。
事故
- 2000年2月11日，正值早高峰，由於電線短路，列車自動控制系統停擺，經過奧克蘭三角線的所有列車被迫以手動駕駛和低至5－10英里每小時（8.0－16.1公里每小時）的速度通過岔道，工人也被派出手動切換岔道方向。低效的操作模式使列車大幅晚點。[6]
- 2009年2月4日，兩輛北行的列車在前往12街/奧克蘭市中心站的途中（圖上M2→C1與A2→C1），在岔道口刮蹭，兩車部分車廂脫軌。由於其中一車在手動模式，本應起保護作用的列車自動控制系統未能生效，來阻止事故的發生。[7]當列車被移開後，灣區捷運方面發佈了一份說明，表示手動控制的列車超過了等待區，[8]NTSB隨後也派出調查員協助。[9]
- 2017年1月4日，一輛西行往三藩市的10節編組列車在抵達奧克蘭西站時控制失靈，沒有停在指定位置，只有7節車廂進站，也無法再次啟動。事件導致前往三藩市的列車皆受到影響，乘客也不得不改用輪渡、拼車、或巴士來跨過海灣。事後有灣區官員呼籲加建第二條過海隧道，以避免類似的情況[10]。
未來發展
有專家曾提出建立連接麥克阿瑟站、奧克蘭競技場站與海灣隧道之間的快速通道，既可以避免潛在的大面積延誤，也可以在途中增加一個傑克倫敦廣場站[11]。另有計劃指出，可以在三角線區間建立一個短途終點站，既可以增加奧克蘭市中心的車站數量，也可以提高市區班次的密度。[12]
來源
- ↑ Mallett, Zakhary. 2nd Transbay Tube needed to help keep BART on track. San Francisco Chronicle. 2014-09-07 [2017-07-31].
- ↑ Eric. New Feature: BART Track Map. Transbay Blog. 2008-07-23 [2017-07-31].
- ↑ Automatic Train Control in Rapid Rail Transit (PDF). Office of Technology Assessment. 1976-05-01 [2017-06-14].
- ↑ 4.0 4.1 4.2 4.3 BART Sustainable Communities Operations Analysis (PDF). BART. 2013-06-01 [2017-07-31].
Station to station running times can identify areas within the system that may be susceptible to delay resulting from either speed / operating restrictions or from infrastructure issues. One of the key locations within the BART system is the Oakland Wye. The Oakland Wye is a multi-level interchange between West Oakland, 12th Street and Lake Merritt stations. BART provided information on the running times between these stations to identify any possible issues with regards route selection, route clearing and secondary delays. The information indicates that actual performance through the Wye is largely consistent with scheduled speeds. As a result, while the Wye does not cause significant delay to operations, it does result in slower overall speeds that could result in longer cycle times. Scheduled run times through this area do include a 10% padding to account for fluctuations in the running times through the Oakland Wye. Running times at other key locations within the BART system are consistent with the scheduled run times; more information can be found in Appendix A2 (a separate document). A previous BART signal system headway and capacity constraint study (Systra, 2012) identified the Oakland Wye is critically important to BART’s current operations and future growth in train service. The underlying signalling is in general well designed, although does have some issues that need to be addressed. The Sequential Occupancy Release System (SORS) overlay, however, was found to have severe and excessive impacts, and in many locations is unnecessarily restrictive. The study found that 「SORS could be made to be much less restrictive, and need not be as restrictive as the underlying signal system」.
- ↑ crawl speed through the Oakland Wye tunnels..... BART Rage. 2007-11-19 [2017-07-31].
- ↑ Cabanatuan, Michael. Improperly Fastened Power Cable Blamed for Horrendous BART Delay. San Francisco Chronicle. 2000-02-11 [2017-12-09].
- ↑ Cabanatuan, Michael. BART trains on time, crash site to be cleared. San Francisco Chronicle. 2009-02-04 [2017-12-09].
- ↑ Cabanatuan, Michael. BART operator ran past wait point in collision. San Francisco Chronicle. 2009-02-05 [2017-12-09].
- ↑ NTSB Launches Investigator to Bart Collision (新聞稿). National Transportation Safety Board. 2017-02-04 [2017-12-09].
- ↑ Cabanatuan, Michael; Veklerov, Kimberly; Ravani, Sarah. BART systemwide meltdown after train gets stuck in West Oakland. San Francisco Chronicle. 2017-01-06 [2017-12-09].
- ↑ Cabanatuan, Michael. Building a bigger, better BART / Experts suggest improving the current system before extending it. San Francisco Chronicle. 2001-01-30 [2017-12-09].
- ↑ Cotey, Angela. Bay Area Rapid Transit's push to invest in state of good repair, capacity improvements. Progressive Railroading. 2012-07 [2017-12-11].
