My primary issue is with the connection at Market Street. Reminds me of the "connection" at Chatelet in Paris. Sure, you look at the map and it looks like all sorts of lines conveniently transfer there. In practice, some of the transfers are very long walks - The walking distance from Line 7 at Châtelet to the RER lines at Châtelet – Les Halles is circa 750 metres . The Central Subway to Market Street Subway transfer isn't 1/2 a mile, it's 1000 feet, but this also requires two pretty time consuming escalator rides.
Once we get into this sort of thing, the transfer becomes very tedious, is a disincentive for usage, and the line is underutilized. That is the crux of why transit advocates cry for the money to be used elsewhere. But if the connection were good, it might just get usage and cries for the line to extend to North Beach and around towards the Marina, which would be a useful legacy for later generations.
But I digress - the title of this article refers to the much ballyhooed connection to Caltrain. Looking at the map, it seems like the "easy" transfer at Union/Powell will allow riders to skip the current roundabout route around Embarcadero to the Caltrain station, and go directly down 4th Street. But this is still fraught with simple mistakes that can really mess up a transit system.
The Central Subway blog brags thus...
the new station located at 4th/Brannan Street will provide an additional transfer point if needed to Caltrain at 4th and Townsend streets.
Brannan Street is 2 blocks away from Caltrain. After our valiant rider has ridden from the Castro to Powell, and navigated the Chatelet of San Francisco to get to the Central Subway at Union Station, they are then dumped off uncermoniously at Brannan, facing a similar connection. But unlike the Powell-Union transfer - they are faced with a 2 block walk that includes crossing a high speed South of Market arterial - Brannan is 2 lanes in each direction and not a fun street to cross - while at the same time looking at their watch wondering if they will make their Caltrain.
Alternatively, the rider could stay on the train until the current station on the East side of King Street - which seems to actually be the most obvious Caltrain transfer point. This requires that the rider wait through the light cycle at Brannan, another one at Townsend, and finally the light at King Street - a horrible intersection including cars rushing to 280 as well as the possibility of being held up by a crossing N-Judah train. Once across King, the rider would then have to cross back across King, a crossing that already exists and is pretty dodgy.
In practice, riders coming from the North will in fact get off at Brannan and run down 4th Street to make their train. Time is money, especially when it comes to missing the Caltrain - I ride my bike and take it on the train because taking MUNI makes it far too likely that I'll miss a train, and missing a train is deadly. I, like most N->S riders, work nowhere near a train station, and rely on a company shuttle that only meets certain trains. If I miss a train by one minute, I am arriving at work at least one hour later.
The best idea, in my opinion, is to remove the station at King, and put a station on Townsend, preferably on the East side of Townsend. This means that the Caltrain transfer for a pedestrian is simply a walk across one lane of 4th Street, much much safer and more direct. It also leaves a fairly close transfer to the N Judah - of course that transfer is not super valuable but it should exist.
Of course, this means that the station would be one block away from a current station - which doesn't make a lot of sense, does it? But if you take a step back, the current station merely exists where it is because it is the transfer spot to Caltrain! If the line were being designed as a whole, from the Bayview to Chinatown, there would not be a station on the East of King, the station would be just East of Townsend. The best play is to *remove* the station at King in favor of one at Townsend.
This would make the transfer much safer for pedestrians, quicker and more reliable, and removes one station from the line. The VTA Light Rail in Santa Clara County is very frustrating to ride exactly because it has too many stations. The station at Brannan adds very little except to add to the end to end runtime for the T/CS line, which decreases reliability and overall attractiveness to the rider. The only "loser" from a removal of the King Street station might be a rider coming from the South headed to Caltrain, who know has to endure the crossing of King before heading to the train - but the population center to the South of that stop is centered around ... the 22nd Street Caltrain station.