San Francisco completes Central Subway tunnel portal entrance
The identical twin TBMs weighed-in at 750 tons each and were affectionately named Mom Chung — for Dr. Margaret “Mom” Chung, the nation’s first Chinese-American physician — and Big Alma — for San Francisco philanthropist and socialist “Big Alma” de Bretteville Spreckles.
Construction on the now-completed Central Subway Portal on 4th Street
2 min to read
Construction on the now-completed Central Subway Portal on 4th Street
The San Francisco Municipal Transportation Agency (SFMTA), which manages all transportation in the city, including the Municipal Railway (Muni), completed the Central Subway tunnel portal entrance, which was the final element to the overall tunneling contract. This portion of the Central Subway Project was completed on-time and on-budget.
The portal, at 4th and Harrison streets, was initially called the “launch box” because it served as the entrance site of two 350-foot-long boring machines (TBMs). Each TBM tunneled 8,500 feet beneath SoMa, Union Square and Chinatown creating the Central Subway tunnels. The identical twin TBMs weighed-in at 750 tons each and were affectionately named Mom Chung — for Dr. Margaret “Mom” Chung, the nation’s first Chinese-American physician — and Big Alma — for San Francisco philanthropist and socialist “Big Alma” de Bretteville Spreckles.
Ad Loading...
Now that the TBMs have completed their 1.5-mile journeys, the launch box has been seismically and structurally reinforced creating the portal where the Muni Metro T Third Line Light Rail Vehicles (LRVs) will enter and exit the Central Subway.
The tunnel portal structure contract called for a final completion date of May 15. However, the crews met expectations by substantially completing the portal structure, constructing the twin tunnels and five cross passages a month earlier.
“It was not only imperative that the portal structure create San Francisco’s next generation of public transit,” said Ed Reiskin, SFMTA Director of Transportation. “It was crucial that we adhered to our commitment to the public. We promised to deliver on-time and on-budget, and the completion of this portion of the project is another milestone that demonstrates we deliver as promised.”
The project was complete within budget estimates of $241 million. The U.S. Department of Transportation announced approval of the Full Funding Grant Agreement of $942.2 million to fund nearly half of the Central Subway Project. The remaining budget is balanced by existing state and local grant funds.
The Central Subway is expected to open to the public in 2019 and will directly serve some of San Francisco’s most densely populated communities including: the Visitacion Valley in the Southeast, east to the Bayview/Dogpatch, and west to the city’s center.
Amtrak will open grant applications March 23 for community projects near the Frederick Douglass Tunnel alignment in Baltimore as part of a $50 million investment tied to the B&P Tunnel Replacement Program.
The Denmark Station $2.3 million construction investment project includes a new 280-foot concrete boarding platform, built eight inches above the top of rail, for improved accessibility for passengers with disabilities and families with small children and much more.
Caltrain and its partners have implemented safety improvements at specific locations in response to known risk conditions, operational needs, and available funding since the agency’s founding.
On a recent episode of METROspectives, METRO Magazine’s Executive Editor Alex Roman sat down with Ana-Maria Tomlinson, Director of Strategic & Cross-Sector Programs at the CSA Group, to explore a bold initiative aimed at addressing those challenges: the development of a National Code for Transit and Passenger Rail Systems in Canada.
Competitive FTA grants will support accessibility upgrades, family-friendly improvements, and cost-efficient capital projects at some of the nation’s oldest and busiest transit hubs.
The 3.92-mile addition will soon take riders west beyond its current Wilshire and Western station in Koreatown, continuing under Wilshire Boulevard through neighborhoods and communities including Hancock Park, Windsor Square, the Fairfax District, and Carthay Circle into Beverly Hills.
Under the plan, all long-distance routes will transition to a universal single-level fleet, replacing today’s mix of bi-level and single-level equipment.
