Central Subway tunnel machines arrive this week

Muni’s $1.6 billion Central Subway Project lurches forward this week with the arrival of its first 300-foot-long tunnel boring machine.

The project, expected to be completed in 2019, will extend the T-Third Street light-rail, include four new stations and hopefully make The City’s public transportation more efficient.

Assembly of the first boring machine will take place in the “launch box,” a 500-foot-long tunnel that sits 40 feet below near Fourth and Harrison streets.

According to residential engineer Sarah Wilson, official work for the project’s southbound tunnel can begin in mid-June.

Wilson said it will take about 10 months to create each tunnel. The second machine is expected to arrive in June.

Both boring machines were given names to bring good luck to the project in March. In a public poll, voters decided to name the first machine “Mom Chung” after Dr. Margaret Chung. Chung was the first Chinese-American female physician in the country, and had her practice in Chinatown.

The second machine is named “Big Alma” after Alma de Bretteville Spreckel, a San Francisco socialite and philanthropist who helped give us the California Palace of the Legion of Honor. Big Alma will work on the project’s northbound tunnel.

Both machines will make their exits at the abandoned Pagoda Palace Theater in North Beach by next April, despite community feedback this month to bury the machines underground.

The San Francisco Municipal Transportation Agency moved the extraction site of the boring machines from the middle of Columbus Avenue to the Pagoda Palace Theater after merchants and residents complained the construction would be disruptive to the neighborhood.

Bids to construct the new stations, tracks and systems opened Thursday. The lowest bidder was from Tudor Perini at $840 million, said John Funghi, project director for the subway line.

The new stations will be located street level at Fourth and Brannan streets, and then underground at Fourth and Folsom streets (Yerba Buena/Moscone), Union Square at Stockton Street (Union Square and Market) and Stockton and Washington streets (Chinatown).

Funghi said this is the final construction contract for project.