The SFMTA is going to be significantly altering how trains run through the Muni Metro tunnels from West Portal through downtown San Francisco when the system reopens for business in August. The stated reason is to allow more social-distancing space, but the changes suggest that the agency is taking this time to rethink the efficiency of the entire system.

Light-rail service on the J,K,L,M,N and T lines is set to resume in time for the school year to start in August, as the SFMTA announced on Thursday. But the J,K, and L will no longer go below ground — the J will terminate at Market and Church, and passengers will have to transfer to an underground train there; and the K and L lines will both terminate at West Portal, where passengers will have to switch trains to go downtown. The goal is to reduce congestion at the system's choke-points, and it sounds like these changes will likely continue after the pandemic ends.

S-Shuttle trains will reportedly be three cars long, and will fill in service between West Portal and Embarcadero, along with M and T trains.

"As we emerge from shelter-in-place, it’s imperative that we take the opportunity to improve our rail service so that we can deliver people to and from school and work reliably,” the SFMTA writes in a blog post. “We don’t want our customers stuck on trains in between stations or crowding on station platforms. By limiting the number of lines that go into the subway, we can meet both of those goals."

We have new SFMTA Director Jeffrey Tumlin to thank/blame for this rethinking of train service, which may or may not solve some of the Muni Metro's notorious reliability issues. And the announcement concedes that Muni train service was highly unreliable prior to the pandemic due to what it says were "structural" limitations from trying to send all seven train lines through the one Market Street tunnel — with three lines that all had to turn back at Embarcadero during rush hour. And the changes will prevent one-car trains on the J, K, and L lines from slowing down traffic for the lines that can take higher-capacity trains.

This graphic compares how the Market Street tunnel fills up during rush hour compared to BART and the Boston MTA. 

"Before the COVID-19 emergency, we had been running more trains per hour in subway than we can process, roughly 40 trains per hour. Often, however, we’re only able to get 35 of [the] trains through," the SFMTA writes. "This makes our service inconsistent and leaves our customers frustrated. To improve reliability and efficiency we need to reduce the number of trains per hour to around 25 to 30 and run higher capacity trains through the subway."

The changes go like this:

  • The M-Oceanview and T-Third will be interlined, with both trains traveling the length of the Market Street tunnel and continuing on the T line down Third Street.
  • The N-Judah will continue on its normal route as before.
  • The L-Taraval and K-Ingleside will also be interlined, and will no longer enter the subway at West Portal. This new interlined route will run from the SF Zoo to City College at Balboa Park Station, and passengers going downtown will have to disembark and board an S or M/T train at West Portal.
  • The J-Church will also no longer enter the subway, and customers can transfer to the M/T line or S at Market and Church, or the N Judah at Duboce and Church.
  • Evening commuters from downtown will choose between M, N, or S trains, and will need to transfer as needed at either Church Street or West Portal.

Here's the map:

Basically the inbound K becomes the L and goes to the ocean, and vice-versa...

The structural limitations of the Muni Metro system have been discussed at length over the years — and last summer we learned that the failed design of the system, which lacks "trunks" or "turnbacks" that would allow disabled trains to get out of the way, dates back to some failures of planning by the agency when BART was constructing the tunnels themselves in the 1970s.

These latest changes, coming at a moment when the entire subway system has been offline for several months, appear to be stopgaps that will at least address the system's notorious congestion problems. But be sure there will be a lot of public complaints as there are with any changes.

Commenters on yesterday's blog post are already expressing their rage about what will likely be a chaotic scene — at least to start — at West Portal Station every morning.

"This really hurts users of the K and L lines," writes commenter Gregory Arenius. "Those trains were often already packed by the time they arrived inbound at West Portal station. Now everyone is going to have to get off the packed train and cram onto another one?"

But the S trains will theoretically pick up this slack, and maybe everyone will get used to this if it means the system actually runs more smoothly?

Also, all the bus replacement service for the train lines will end in August, freeing up those buses to return to service on normal bus lines.

Related: Muni Debates Overhauls To Poorly Designed Subway Rail System