Yes, the time has come. Saturday is the day that the Central Subway will see its first day of full, integrated operation with the rest of the Muni underground system — and we're taking bets about how smoothly/terribly this will go, especially in the rain.

The SFMTA doesn't exactly have a stellar track record when it comes to rollouts of new trains and systems. And while the Central Subway "soft opening" in November seemed to go OK, trains in the new tunnel have spent the last six weeks just pretending to be a subway line — shuttling people only between 4th and Brannan and Chinatown, for free, on weekends only.

Starting Saturday, as previously reported, the Central Subway begins life as a new arm of the T-Third train line — and T-Third trains will no longer be seen in the regular main-line tunnels between West Portal and Embarcadero. The new T-Third will still terminate at one end at Sunnydale, but passengers coming from Sunnydale will now be able to ride directly to Union Square or Chinatown without the detour around the Embarcadero, via the new Central Subway, and vice versa. Those looking to go to the ballpark or Folsom & Embarcadero will need to take the N instead.

The K-Ingleside, in this revamped system, will now terminate and turn around at Embarcadero. See the new map below.

The integration will cause confusion for many, no doubt, and Saturday will be the first test of getting people used to transferring through the labyrinth of the new Powell Street/Union Square passages and long escalator that connect the old Powell Station and the new Union Square station deep underneath Stockton Street.

As the SFMTA notes, this new train connection is going to be a great new convenience for the many Chinese Americans living in Visitacion Valley and the Bayview who "rely on public transportation to visit Chinatown for their basic necessities, groceries, and in-language services."

The agency is promising that service on the new T-Third/T-Chinatown will run Monday through Friday, 6 a.m. to midnight, every 10 minutes; and Saturdays and Sundays, 8 a.m. to midnight, every 12 minutes."

Also, on Saturday at 12:30 p.m., there will be a ribbon-cutting ceremoney at Sunnydale Station at Sunnydale Avenue and Bayshore Boulevard.

Previously: Take A Look at Your New Muni Subway Map — With Central Subway Starting Some Service Saturday

Top image via SFMTA