BART’s new hours start today: What it means for your commute

As the massive seismic retrofit of the Transbay Tube gets underway, BART today will begin subbing buses for trains in its first hour of service on weekdays and single-track trains after 9 p.m. Thursday through Sunday.

The service changes will allow the agency to complete the more than $300 million retrofit of the Transbay Tube, shoring the essential transit artery in the event of a major, once-in-1,000-years earthquake, while also performing needed repairs and upgrades throughout the system.

It takes crews some time to set up equipment at night and then break it down before the start of the morning commute, creating a limited window of “wrench time” to actually get to work. Adding extra hours for workers will enable the agency to get 43 percent to 62 percent more work done and shave months off construction, officials said.

The remaining seismic retrofit work in the Transbay Tube is the last project in a host of earthquake upgrades voters approved in 2004 as part of $980 million in Measure AA bonds for the $1.2 billion program.

Crews will line key sections of the 3.6-mile tube with curved steel plates, using grout to adhere the plates to the tube’s concrete walls, and a polymer product under the tracks to prevent against possible leaks.

They’ll also install an upgraded pumping system that will allow larger

quantities of water to be removed more quickly from the tube, should water make its way in.

Throughout the rest of the system, workers will replace segments of rail and upgrade power substations, rebuild interlocking components on the tracks and replace high-voltage transformers, upgrade fire and tunnel lighting systems, and replace stretches of its electric cables, among other projects.

It’s largely work voters approved in 2016 under Measure RR, a $3.5 billion

bond aimed at improving reliability on the aging system.

The work is expected to last three and a half years, but BART officials say the extra time spent working will save them time and money in the long-run, delivering the projects faster and improving passengers’ commutes.

Some 2,900 passengers board BART between 3:45 a.m. and 4:45 a.m., with the vast majority boarding in the East Bay and more than half disembarking in San Francisco.

BART will run buses from select stations to destinations in the East Bay, Peninsula and San Francisco.

Single-tracking after 9 p.m. through the tube Thursday through Sunday mean trains will come every 24 minutes, rather than every 20 minutes, and some passengers will need to make an extra transfer to get to their destinations.

Extra trains will be added Friday nights.