Starting Wednesday night the subway work will be going on 24/7. Some of the work and equipment you can see above ground, but most of it is so far down that you can't see it, hear it, or feel it.
On the surface of Fourth Street, just South of Market, you would never know that a tunnel boring machine is building a tunnel about 85-feet below. Video from the San Francisco Municipal Transportation Agency shows the boring machine. As it makes steady progress, it will pass beneath Union Square this weekend at 95-feet below the surface.
"We're very excited, we're about to enter what we call the BART undercrossing," said John Funghi the Central Subway program director.
The machine is now moving north from Fourth Street, crossing underneath Market Street and existing transit tunnels.
"There's four existing tubes on Market Street. We have BART and the two tubes on Muni. And basically, a perpendicular crossing of those four tubes," said Funghi.
The tunneling began earlier this year at Fourth and Harrison. After passing underneath Union Square, it will eventually end at Powell and Columbus, where the tunneling machines will resurface at the old Pagoda Theater site in June.
Stockton Street between Market and Geary has been closed to vehicular traffic since January to accommodate a variety of subway-related work, but it will re-open Friday for the holiday shopping season, closing again January 2. That's a true holiday gift for one FedEx delivery man.
"We extremely heavy this time of year and it would be a blessing for them to open Stockton," said Jeff Cameny, a FedEx employee.
But don't hold your breath for the subway opening, that's not until January 2019.