muni_generic.jpgThe excavation of nearly an entire block in San Francisco’s South of Market neighborhood is starting Tuesday in preparation for the tunneling of the city’s Central Subway.

The $1.6 billion project is creating a new branch of San Francisco Municipal Railway’s T-Third light-rail line from Fourth and Brannan streets to Chinatown, with underground stops at Moscone Center and Union Square.

The subway is not expected to be completed until 2019 but workers are starting a major part of the project Tuesday that will impact traffic in the neighborhood.

Crews will be excavating a space about 500 feet long, 50 feet wide and 40 feet deep on Fourth Street between Harrison and Bryant streets, then constructing a launch box at the site where tunneling will begin next year, according to Muni officials.

People living, working or traveling in the area are advised that an increase in noise, dust and truck traffic is expected once the construction starts.

Several Muni bus lines have been rerouted around the area, and motorists are also advised to take alternate routes.

Frequent construction updates and information about impacts on traffic are available online at

Dan McMenamin, Bay City News

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