奥克兰三角线位于加州奥克兰地下，是湾区捷运系统里的重要区间。列车可通过此三角线前往[1][2][3]:45–46[4]
- 北行-12街/奥克兰市中心站（里奇蒙方向 或 匹兹堡/湾角方向）
- 西行-奥克兰西站（旧金山方向）
- 南行-美丽湖站（弗雷蒙 或 都柏林/普莱森顿方向）
因为所有列车都会经过这里，所以此三角线是湾区捷运系统里最重要的区间之一，但也因为复杂的结构成为了全线速度的瓶颈。[4][5]
结构
.svg)
大部分轨道的设计速度是27英里每小时（43千米每小时）。由于设计失误，控制中心规定的限速是18英里每小时（29千米每小时）。虽然失误随后被修正，基于安全考虑，这个限速依然不变。[4]唯一“高速”的通道是从奥克兰西前往12街/奥克兰市中心的轨道（图中MX→CX），允许的速度达到36英里每小时（58千米每小时）。[4]
另外，MX轨道和M1轨道之间也有渡线，加上麦克阿瑟站附近繁多的岔道，在特殊情况下（如2018年金州勇士胜利游行时），CX→MX→M1轨道也会被作为下行前往旧金山的通道，以提高通行的效率，同时北上的列车将只使用M2→C1轨道。
历史
奥克兰三角线曾多次发生事故，而由于其重要性，每次事故都会波及整个系统。有专家曾提出建立多个通道来降低三角线故障所带来的影响。
事故
- 2000年2月11日，正值早高峰，由于电线短路，列车自动控制系统停摆，经过奥克兰三角线的所有列车被迫以手动驾驶和低至5－10英里每小时（8.0－16.1千米每小时）的速度通过岔道，工人也被派出手动切换岔道方向。低效的操作模式使列车大幅晚点。[6]
- 2009年2月4日，两辆北行的列车在前往12街/奥克兰市中心站的途中（图上M2→C1与A2→C1），在岔道口刮蹭，两车部分车厢脱轨。由于其中一车在手动模式，本应起保护作用的列车自动控制系统未能生效，来阻止事故的发生。[7]当列车被移开后，湾区捷运方面发布了一份说明，表示手动控制的列车超过了等待区，[8]NTSB随后也派出调查员协助。[9]
- 2017年1月4日，一辆西行往旧金山的10节编组列车在抵达奥克兰西站时控制失灵，没有停在指定位置，只有7节车厢进站，也无法再次启动。事件导致前往旧金山的列车皆受到影响，乘客也不得不改用轮渡、拼车、或巴士来跨过海湾。事后有湾区官员呼吁加建第二条过海隧道，以避免类似的情况[10]。
未来发展
有专家曾提出建立连接麦克阿瑟站、奥克兰竞技场站与海湾隧道之间的快速通道，既可以避免潜在的大面积延误，也可以在途中增加一个杰克伦敦广场站[11]。另有计划指出，可以在三角线区间建立一个短途终点站，既可以增加奥克兰市中心的车站数量，也可以提高市区班次的密度。[12]
来源
- ↑ 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 (新闻稿). 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].
