In March, BART began work installing heavy steel plates inside the tube to make it stronger against an earthquake. BART originally estimated the project to last 14 months, but finished in eight.
"We are thrilled the work was finished early and BART passengers will no longer be inconvenienced from this phase of our larger project to make the tube as resilient as possible," said Tom Horton, group manager of BART's Earthquake Safety Program. "I want to thank the hard working crews and the California engineering contractors who made it happen and, of course, our passengers for their patience over the past eight months. With this phase of strengthening complete, BART will begin planning the next stages of this multi-year effort. All work will be planned to minimize impact to our riders. The result will be a stronger, safer Transbay Tube."
Each work night, engineers raced against the clock to set up a construction site within the tube, complete the daily tasks and then dismantle the set up before passenger service started. Crews of 15-20 people were involved each night, using hi-rail trucks to bring in the steel plates, weighing four tons each and drill the bolts that fasten them to the interior of the tube. All plates have now been welded together from end-to-end, completing the project.
This work is part of BART's Earthquake Safety Program to strengthen the tube, 34 stations, 22 miles of elevated track (including 1,918 support columns) and parking structures and other facilities.