To be fair, service between Chinatown and Mission Bay would be a bit better than a 1-car train every 10 minutes. At peak, you’d probably have 5-minute headways on both the short and long loop, with the possibility of an additional peak loop. So, a fair amount of theoretical service, but having it work out operationally is a different question.

The most discomforting aspect of this project is that as it is currently planned it cannot provide a quality of service as people expect from real subways.

It is not to say that Muni shouldn’t consider having through service to the Bay View, but the infrastructure has to be built to provide flexibility to operate independently at a higher frequency with more capacity. Are there enough through riders to demand through service?

4th & King intersection is already a mess, with freeway traffic and LRV traffic. Think of the quality of service Chinatown will get when trains stuck at 4th & King.

The notion of direct service from the Bayview sounds good, but doing so would compromise service quality for most of the passengers traveling between Market Street and Chinatown. If the Chinatown segment can support 3 or 4 car service, it is shameful to only have 2 car long platforms because the southern portion can only support 2 car trains.

A well known problem with the current Muni Metro is the lack of turnarounds in the subway area. Imagine if there’s a pocket track just south of Castro, Muni would be able to provide much higher quality subway service. It doesn’t appear the Muni would build the infrastructure to support an independent operation to 4th & King if some point in the future it is desirable to have one.

You do if you’re Muni.

That said, there would at the least be a long loop (between Chinatown and Bayshore) and a short loop (between Chinatown and Mission Bay), with a possible even shorter peak hour loop.

Your comments on service, operations, and the worth of the project are good. These are actually issues I plan to touch on more in the upcoming posts in this series, once getting the basic project description stuff out of the way.

So will the Central Subway’s capacity will be limited by the operating constraints and ridership demand of the rest of the T-Third line? Can the Central Subway replace some surface buses while maintaining sufficient capacity and rider experience?

I think if Muni cannot run 4 car trains every 3 minutes in the Central Subway (Chinatown to Market Street or 4th & King), it is not worth building. You don’t waste money to build a subway infrastructure for single car trains running every 10 minutes, while requiring the existing buses run as or more frequently to handle ridership.