The Transbay Tube is BART’s most critical asset. Although the tube is structurally sound, in a very large and very rare earthquake event, the outer shell and concrete liner are predicted to crack, causing leakage.
To address concerns of flooding in the event of a 1,000 year earthquake, BART has awarded a 313-million dollar contract (to Shimmick Construction and California Engineering Contractors Inc.) for a massive project that will retrofit the Transbay Tube.
To give crews the time needed to get the work done, BART plans to open the entire system one hour later on weekdays for the project’s duration. This means changing from a 4:00 a.m. to a 5:00 a.m. start of service for a period of up to 3.5 years.
This extra hour each night will extend the available work window by at least 20% and save the project a minimum of $15 million.
The specific date for when the service change will take effect is February 11, 2019. View the board presentation.
The board received an update on the proposed mitigation options at the July 12, 2018 meeting. View the board presentation.
What’s Being Done
This project will help ensure any earthquake-caused leaking is slowed to a point that will give people time to evacuate, with a second priority of keeping the leakage low enough that the tube can eventually be repaired.
The work itself involves installing an inner steel lining to the 3.6 mile-long tube, which is made of a reinforced concrete liner with an outer steel shell.
It also involves the construction of a new pumping system that will allow larger quantities of water to be removed more quickly from the tube.
One Hour Goes a Long Way
Adding this one hour a will shorten the project timeline by 4 months.
It will also give our crews more time for track inspections, preventative maintenance, and Measure RR bond funded rebuilding projects throughout the system such as power cable replacement through San Francisco and rail replacement. The extra wrench time will speed these projects up by 40%, provide a 12% cost savings and increase the maintenance productivity of our crews by 43-62%.
In September of last year, an independent study by Transportation Resource Associates was presented to BART’s board.
Among its findings, continued maintenance reforms are essential for BART’s future success and proper maintenance requires the agency to plan service adjustments.
The decision to start service later, as opposed to ending it sooner each night is largely based on data showing there are far more riders (between 5,000 and 6,000) during the last hour of our service window than the 2,800 riders we carry in the first hour.
Beyond that, the work will actually begin at 9:30pm each weeknight when we start single tracking until closing as work trains carry equipment into the tube. This means closing an hour earlier would not give us that extra hour of work time.
Any gained time to the project is at the end of the work day which is after 4:00am.
Impacts to Riders
We understand this project will impact our riders.
In addition to the later weekday morning start time, BART will be single-tracking trains through the tube each weeknight from 9:30 p.m. until close of service at midnight. This will allow crews to shuttle in equipment via the closed track. During this time, trains will run every 24 minutes instead of the every 20 minutes they run now.
About 2,900 passengers enter our system in that first hour of service.
Over 2,400 of them begin their trips in the East Bay and 64% of our first hour riders disembark at downtown San Francisco stations.
Our board is considering options for alternative bus service in the 4 to 5 o-clock hours.
One of those options would establish new A-C Transit routes from the East Bay into San Francisco… and enhance existing early morning A-C Transit, Muni and Samtrans service.
Another more robust option would do the same but also add 4 express bus service lines into San Francisco from the Pittsburg/Baypoint, Pleasant Hill, Dublin/Pleasanton and Fremont stations.
BART conducted extensive outreach during the month of April which included surveys, in-station outreach, multilingual media ads, community presentations, and meetings with airport employees, hospitality and service workers, business owners and unions.
A summary of the mitigation options and survey results were presented at the July 12, 2018 board meeting. Board members will use the information to decide what level of alternative bus service to provide during the 4am hour. The plan will be finalized in September.