Passenger Trains > Caltrain's 4th & King S.F. Terminal to go Underground?

Caltrain has joined with Prologis, Inc. with plans for a massive redevelopment of their
San Francisco 4th and King terminal area in a project that has been proposed for years. 
Prologis is the world's largest industrial real estate investment trust.

The station will remain at the same location with the depot tracks moved underground to 
accommodate the development above.  San Francisco has some of the highest land values
in the nation(comparable to Manhattan) with this considered to be a prime location.

According to Prologis, the firm expects to construct between 7 and 8 million square feet
at full build-out, including approximately 4 million square feet of commercial office space 
and roughly 2,500 dwelling units. The tallest tower would rise at 4th and King Street
at up to 850 feet in height.

The project is fully compatible with the Portal Project to extend Caltrain downtown to the
Salesforce Transit Center in which case the new station would become the last intermediate 
stop on the line.  If that project remains seriously delayed(or never happens) the new
station would remain as the San Francisco terminal.

Caltrain will construct a temporary station(with presumably fewer tracks) on the King Street
side moved back a short distance from 4th Street to allow work to begin.  With quick turnaround
times from the new EMU's the present 12 depot tracks is more than what is needed.

From sfyimby.com(expect a subscription request ad to pop up on the right side of the screen
at some point during your read):
https://sfyimby.com/2026/03/deep-dive-into-caltrains-san-francisco-railyards-redevelopment.html

Two attached images look at the present day looking east at 7th and Townsend and the proposed future
entrance to the new underground station at 4th and Townsend/King.



Edited 2 time(s). Last edit at 03/13/26 11:22 by milepost20.

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I know San Francisco needs housing, but its like nobody learned that putting stations underground creates a terrible user experiance. 

Meanwhile the old Bayshore Yard site continues to sit empty. 

quake risks and terrorism risks increase, suck

Brisbane, CA, where Bayshore yard lies within, sued CHSRA for planning to put its northern EOL stabling/light maintenance yard at Bayshore, as the city planned to redevelop the land.
Eventhough Brisbane and CHSRA reached settlement, there is no telling whether the city will sue Caltrain if it also move its yard to Bayshore.

mbrotzman Wrote:
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> I know San Francisco needs housing, but its like
> nobody learned that putting stations underground
> creates a terrible user experiance. 
>
> Meanwhile the old Bayshore Yard site continues to
> sit empty. 

SF keeps packing more and more and more people into their city, but is FAILING to develop faster transit to move them around.  This is just another example.  I used to do a truck delivery route in SF for years--all the hard spots--and it's gotten even worse now.  So glad I'm no longer there.  It's very slow trying to get around when it's busy.

Instead of focusing on this project, the City should develop subways under GEARY BLVD., VAN NESS BLVD., out to MARINA GREEN via the Fort Mason tunnel, all the way to the Presidio and bridge, HAIGHT STREET into Golden Gate Park, and 19th Avenue to connect the lines.  That would be aggressive, forward thinking, and it woiuld help people get to all parts of the City.

The city of Brisbane and the CHSRA reached an agreement in late 2024 for the
high speed rail maintenance facility to be located on the east side of the Caltrain
main next to the tank farm well away from the city's redevelopment plans.  Caltrain's
CEMOF shops in San Jose should serve them for years to come and I'm not aware of
any proposals for Caltrain to occupy any land at the old Bayshore Yard site. 

 https://www.trainorders.com/discussion/read.php?4,5918251,5918252#msg-5918252

Thanks for the link to the old discussion. The topic becomes where to store the CaHSR equipment between arrivals and departures at the 'downtown' station. Whether to hold the equipmemt in a downtown tunnel or to run it out to the proposed HSR facility at the old Bayshore yard. Not something to be concerned about today but eventually it's a question.

mbrotzman Wrote:
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> I know San Francisco needs housing, but its like
> nobody learned that putting stations underground
> creates a terrible user experiance. 

This is all strange. No more downtown (underground) station at Salesforce Transit Center?

It's possible to put real estate on top of current 4th & King Station. Why go through the trouble of routing the trains underground, which should be saved for parking?

Caltrain electrification (instead of steam or diesel) has made the idea of underground stations more viable. Anyway, even if my opinion is meaningless, I ought to speak out so I don't regret it later.
 

mbrotzman Wrote:
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> I know San Francisco needs housing, but its like
> nobody learned that putting stations underground
> creates a terrible user experiance. 
>
I totally disagree.  Two underground stations which provide pleasant user experiences are Jefferson (formerly Market East) in Center City Philaldelphia and Grand Central Madison in New York City.  Attached is a photo of Jefferson Station.

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Only model railroads should be in the basement.

coach Wrote:
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> SF keeps packing more and more and more people
> into their city, but is FAILING to develop faster
> transit to move them around.  

With a US population increase of 22%-25% in the past 25 years, all metropolitan areas are dealing with an increase in population but with little or no related increase in spending for increased infrastructure to handle that. SF is by no means alone in that struggle. 

Are you able and willing to pay a 25% increase in taxes to cover such increased infrastructure, as well as support the use of land needed for it?

cchan006 Wrote:
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> This is all strange. No more downtown
> (underground) station at Salesforce Transit
> Center?

Original post by milepost20 has the answer.

> It's possible to put real estate on top of current
> 4th & King Station. Why go through the trouble of
> routing the trains underground, which should be
> saved for parking?

Is it possible that significant underground work needs to be done at that paticular location for the project that it was decided might as well put the station underground as part of that work?

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longliveSP Wrote:
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> Original post by milepost20 has the answer.

Saw that already before I replied. To me, it raises more questions.

> Is it possible that significant underground work
> needs to be done at that paticular location for
> the project that it was decided might as well put
> the station underground as part of that work?

And it's not clear to you either, so it's not The Answer. I raised that and called the proposal "strange" instead of accepting it face value.

I've gotten good look the area in the past, inluding catching a MUNI Breda LRV last year as proof here on TO. I've walked from 4th & King to the Embarcadero, Transbay Terminal, Moscone Center, two different BART stations, as well as riding the "30 Stockton" bus countless times. But I didn't document those on TO, so no proof., but it's up to TO members to judge my opinion.

The "real estate angle" is always suspicious, more so here in CA than other places.

cchan006 Wrote:
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> The "real estate angle" is always suspicious, more
> so here in CA than other places.

Anytime I see real estate interests aligning with public entities I know the public will be screwed. Politicians ascensions into office are funded by real estate developers to ensure their projects are chosen and public assets are given away at bottom dollar rates.  
 

Todd Clark
Canyon Country, CA
Trainorders.com

Isn't this part of San Francisco built on land that was reclaimed from the Bay? Could that be a problem?

Anything flat and near the Bay is fill land, from one of the many times of filling in the marsh areas. The extension would begin in the fill area and end near the rock bluff near the SF side of the Bay Bridge. There's a great big building to mark the spot. Happens to be next to the building that's leaning because somebody signed off on a bad foundation design.

Thinking it boils down to one question, is ther money involved?

Read this with interest in the SF Chronicle early this week. The current station at Fourth and King works but leaves a lot to be desired aesthetically. Seems pretty clear to me at least, that Caltrain needs lots of linear real estate in order to get their ROW down far enough to access Sales Force. This is a good location for that.

At eight hundred and fifty feet, someone is going to make a ton of money in real estate dollars on this project. Hopefully CalTrain can get a pleasant, modern Station and a good head start toward downtown in the deal. This station handles large loads of folks as it services both Chase Center and the Giants ballpark crowds so whatever is built will have to be designed to get large crowds from station level to street level in a hurry.

cchan006 Wrote:
-------------------------------------------------------
> longliveSP Wrote:
> --------------------------------------------------
> -----
> > Original post by milepost20 has the answer.
>
> Saw that already before I replied. To me, it
> raises more questions.
>
> > Is it possible that significant underground
> work
> > needs to be done at that paticular location for
> > the project that it was decided might as well
> put
> > the station underground as part of that work?
>
> And it's not clear to you either, so it's not The
> Answer. I raised that and called the proposal
> "strange" instead of accepting it face value.

Actually, it is very clear. The only way the Caltrain will reach the desired station of Salesforce Transit Center is underground tunnel. And that is going to have to start somewhere. It is not going to start AFTER 4th & King. It is going to have to head underground BEFORE that. 

longliveSP Wrote:
-------------------------------------------------------
> coach Wrote:
> --------------------------------------------------
> -----
> > SF keeps packing more and more and more people
> > into their city, but is FAILING to develop
> faster
> > transit to move them around.  
>
> With a US population increase of 22%-25% in the
> past 25 years, all metropolitan areas are dealing
> with an increase in population but with little or
> no related increase in spending for increased
> infrastructure to handle that. SF is by no means
> alone in that struggle. 
>
> Are you able and willing to pay a 25% increase in
> taxes to cover such increased infrastructure, as
> well as support the use of land needed for it?

Yes, but the tax increase would not be 25%.

longliveSP Wrote:
-------------------------------------------------------
> Actually, it is very clear. The only way the
> Caltrain will reach the desired station of
> Salesforce Transit Center is underground tunnel.
> And that is going to have to start somewhere. It
> is not going to start AFTER 4th & King. It is
> going to have to head underground BEFORE that. 

But why does it have to detour via 4th & King? There are TWO light rail lines(T and N) that exist already. The N can be extended west on the ground for a new Caltrain/MUNI transfer station. Current T vs N junction can be modified, so even T can access the new transfer station. Caltrain from there can reach Salesforce more directly. Instead of  mere "real estate angle," how about actually improving/changing the rail service?

Where's your analytical thinking? Merely using someone else's idea to "argue facts" is how bad ideas get implemented.