Will Caltrain Ever Take You Downtown? [PedestrianObservations]
If you want to get to downtown San Francisco from a Caltrain station, you’re out of luck. There is a plan to fix this—but this plan is running into the cost problems that plague all American rail tunnels.
The 4th & King Caltrain terminal is frustratingly just outside the city’s Central Business District. Many great American cities such as New York, Chicago, Boston, and Washington, D.C. have main train stations right in the middle of their CBDs. People who travel by train can walk from these stations to many destinations. San Francisco stands as an exception.
Since 1900, the owners of the Peninsula rail line—then Southern Pacific, today the Joint Powers Board that runs Caltrain—have wanted to extend the line deeper into the center of San Francisco. Given Caltrain’s alignment today, it still can’t be the primary mode of transportation between the city and the Peninsula, even after rail electrification. The one mile between 4th and King and Transbay makes a world of difference. The Transbay Terminal has 170,000 jobs within a half-mile radius of its station; 4th and King has only about one-tenth as many, roughly the same as Palo Alto.
The present-day project called the Downtown Extension, or DTX, calls for a 1.3-mile tunnel to the Transbay Terminal, meeting buses traveling over the Bay Bridge. Caltrain and California High-Speed Rail would both use DTX to access the Central Business District. Caltrain would stop at a new underground station near the current terminal at 4th and King as well as at Transbay, while HSR would exclusively serve Transbay.
Suburban park-and-riders routinely drive long distances between their houses and the train station, but transfers at the destination end are worse than the first leg of their journey. Transportation researcher Reinhard Clever notes that in Toronto, suburban commuters take commuter rail if they work within just less than half a mile (700 meters) of Union Station; they do not transfer to the subway to get to jobs farther away.
Likewise in Boston, the mode share of commuter rail is lower on lines feeding North Station, lying two subway stations north of the Boston CBD, than on lines feeding South Station, which is walking distance to the CBD. We can expect a large increase in ridership, independent of everything else, if Caltrain enters the San Francisco CBD.
Unfortunately, the project as it stands today has deep flaws. Urban rail tunnels require a lot of safety measures: this means cities need to ensure no new infrastructure is built in their way, such as building foundations. But San Francisco has built new downtown skyscrapers in the last decade, which constrain the possible DTX alignments. Curves will have to be tight. There is no chance under the current plan to connect the station to onward destinations, perhaps the East Bay with a second Transbay Tube. Even short tail tracks, allowing trains to enter the station at speed, are no longer possible; trains will have to slow down before arriving, lengthening everyone’s commute.
But some compromises can be fixed. The HSR business plan claims that most Caltrain trains would have to keep terminating at 4th and King, since there is no room for all planned Caltrain and HSR trains. This comes from excessive turnaround times. Commuter and even intercity trains routinely turn in 5 minutes when they have to, in Germany; in Japan, they can turn in 12 minutes, while being cleaned. In contrast, HSR plans on 40-minute turnaround times. Trains would hog scarce platform tracks at the station, forcing some trains to wait outside. This can be fixed with better loading and unloading procedures and fast cleaning.
Moreover, the cost is very high: $3.9 billion, making DTX the most expensive rail project in the world per mile outside New York. This could be justified if ridership were very high, perhaps 70,000 per day; Caltrain electrification is $2 billion and the ridership projection, without DTX, is 100,000, up from 60,000 today.
Diesel trains cannot use DTX, because their fumes would concentrate in the tunnel. Thankfully, DTX is sequenced to open well after Caltrain completes electrification, assuming electrification finds money soon. If the station is configured for high capacity so all trains can serve this station, it will be a useful complement to Caltrain electrification and High Speed Rail. It would likely see many riders, since there are just far more jobs near Transbay Terminal than near 4th and King—it just isn't clear how high the city can expect it to be.
Alon Levy is a mathematician with a strong interest in urbanism and mass transit, and currently works as a freelance writer. He contributes to the Bay City Beacon as a weekly transit columnist for Pedestrian Observations. You can find more of his writing supporting walkability and good transit at https://pedestrianobservations.wordpress.com
Correction: an earlier version of this article listed the cost of DTX as $2.6 billion. It has been updated to a more accurate $3.9 billion.