The Caltrain commuter rail system links San Francisco with San Jose / Gilroy and the cities in between. Originally built in 1863 by Southern Pacific, today the system offers local and express service between the numerous residential and commercial areas in the SF Peninsula and Silicon Valley.

Like BART, Caltrain has undergone astronomical ridership growth in recent years. With 60,000 daily riders, Caltrain’s single line ranks among the busiest rail corridors in the US, and a ridership of 110,000 is anticipated by 2050. To meet this target, Caltrain will undergo the most significant capital construction in its history over the next 15 years.

Caltrain’s roadmap, like BART’s, will be divided into several parts. This article focuses on Caltrain’s current efforts to electrify the system between SF 4th & King and Tamien Stations. Upon completion, Caltrain riders can expect a 20 percent decrease in travel time, as well as additional service at currently underserved stops. This article will also lay out a service plan that would provide frequent and convenient service to the residents along the corridor.

This article will refer heavily to topics discussed on the Caltrain-HSR compatibility blog; check out the articles there for a more detailed and technical analysis of the information presented below.

Capital Construction: Electrification and Level Boarding

Caltrain currently uses diesel-electric locomotives, but by 2020 or 2021, electric multiple units (EMUs) will begin running along the corridor. While electric service is more environmentally friendly than diesel service, the most prominent advantage of EMUs is their ability to accelerate quicker. By doing so, a train can make more stops and serve more riders without incurring large time penalties. For instance, current Baby Bullet trains will still be able to travel from SJ to SF in one hour, while stopping at 9 stops instead of 5 (see the table below). Local service will also experience a significant upgrade, with end-to-end local travel time expected to be reduced by 15 minutes or more.

Station Baby Bullet (Diesel) Baby Bullet (Electric) San Jose 7:03 7:03 Santa Clara – 7:08 Sunnyvale 7:13 7:14 Mountain View – 7:18 Palo Alto 7:23 7:25 Redwood City 7:30 7:31 Hillsdale – 7:37 San Mateo 7:39 7:41 Millbrae 7:47 7:46 22nd St – 7:58 San Francisco 8:04 8:03

In addition, Caltrain intends to upgrade the platforms at every station along the line. Currently, all stops use low-level platforms, and riders must walk up internal stairs to reach the train floor. The gradual transition to high-level platforms will enable riders to simply step into the future EMUs, as currently seen on BART. In conjunction with additional train doors, Caltrain’s upgrades will speed up boarding, reduce dwell times at stations, and further reduce travel time.

Ridership Potential

Currently, Caltrain runs 5 trains per hour (tph) in each direction during rush hour. After electrification, Caltrain anticipates running 6 tph in each direction, with some capacity reserved for additional HSR trains to and from Los Angeles in the same corridor. Because the Caltrain corridor will carry a mix of local, express, and high-speed trains, a new timetable will need to be developed. Adopting a schedule with even headways would enable Caltrain to provide more timed connections to BART trains at Millbrae and other transit agencies around the Bay.

As previously discussed, transit ridership is correlated with station location. Many Caltrain stops are located within downtowns and can generate significant ridership, and thus need to be frequently served in the new timetable. Caltrain’s annual ridership reports reveal that Baby Bullet service is correlated with higher ridership. Yearly ridership analyses have consistently ranked the top 10 stations as follows:

San Francisco (13,575) Palo Alto (7,197) Mountain View (4,570) San Jose (4,160) Millbrae (3,536) Redwood City (3,233) Sunnyvale (2,881) Hillsdale (2,706) San Mateo (2,061) Menlo Park (1,762)

Ridership growth has been uneven, however. Several underserved stations, especially in Santa Clara County, have lagged behind in growth since 2004. Passengers are not distributed across trains evenly, with express trains overcrowded but plenty of spare capacity on commute-direction local trains or reverse commute-direction express trains to San Jose that skip too many stops in Silicon Valley. When service is expanded after electrification, Caltrain must prioritize stops that serve high population or large numbers of jobs.

As the infographic of census data above shows, the Santa Clara County and Downtown SF stations are most likely to have high ridership. In particular, several conclusions can be drawn from the ridership reports and census data.

Most Caltrain riders are headed to and from SF, and the Downtown Tunnel Extension (DTX) to the Transbay Transit Center should be fast-tracked ASAP. The Santa Clara County stations, from Menlo Park to San Jose, all have a nice mix of nearby job and population centers. They should all have frequent service (minimum 15-minute peak service and 30-minute, perhaps 20-minute, off-peak service). The San Mateo County stations resemble the Santa Clara County stations, but with fewer job and population walksheds in general. Given that Caltrain primarily serves a market between Silicon Valley and SF today, most trains should run express between Redwood City and SF.

The Mid-Line Overtake

Because Caltrain features several different types of service, some faster than others, there exists four-track sections along the line (takeovers) that enable express trains to bypass local service. Currently, takeovers exist at Bayshore Station in the north and Lawrence Station in the south, but there express trains run through there and riders cannot transfer between trains.

Ridership analysis indicates that a two-platform, four-track transfer point in the middle of the line, either at Redwood City or Hillsdale, would create the most efficient service plan. Riders at local stations would be able to transfer to an express train across the platform without a time penalty, enabling quicker travel times. An overtake would also be used for future HSR trains to bypass slower Caltrain service.

For the next section, it is assumed that additional tracks will be constructed between Redwood City and Hillsdale in preparation for additional express and HSR service.

Timetables and Takts

Caltrain has two different service proposals it can consider, both of which provide very frequent and convenient service between any two stations along the corridor.

Transfer at Redwood City: Clem Tillier of the Caltrain-HSR Compatibility blog has drawn up a service plan for the Caltrain corridor similar to that on the NYC Metro-North commuter rail system. The corridor is effectively split into two zones, with local and express service. Redwood City becomes a transfer point between local and express trains, with four tracks at the station. A four-track section exists between Hillsdale and Redwood City.

Silicon Valley Express (15 minute headways peak, 30 minutes off-peak): Direct SF – SJ trains run local in Santa Clara County, where all stops have high population and job centers, while bypassing most stops in San Mateo County. (Author’s note: The train should stop at Downtown San Mateo as well.) Every station south of Redwood City effectively gets Baby Bullet service, with 15-minute headway service and travel to SF under one hour. Stations in southern SJ (Tamien, Capitol, Blossom Hill) are served during peak hours in the commute direction only, and stops in southern SF (22nd St, Oakdale) are served during peak hours in the reverse commute only.

(15 minute headways peak, 30 minutes off-peak): Direct SF – SJ trains run local in Santa Clara County, where all stops have high population and job centers, while bypassing most stops in San Mateo County. (Author’s note: The train should stop at Downtown San Mateo as well.) Every station south of Redwood City effectively gets Baby Bullet service, with 15-minute headway service and travel to SF under one hour. Stations in southern SJ (Tamien, Capitol, Blossom Hill) are served during peak hours in the commute direction only, and stops in southern SF (22nd St, Oakdale) are served during peak hours in the reverse commute only. San Mateo Local ( 30 minute headways): Trains serve the less busy stations between SF and Redwood City every 30 minutes (possibly 15 during the peak), with a timed connection to Silicon Valley express trains at the latter. Reversing trains at Redwood City would be difficult however, and thus these trains should be extended to a new terminal at East Palo Alto (not pictured in the diagram). From there, the line could be extended via Dumbarton Rail to Newark, Fremont, and Union City (to be discussed in a future post).

30 minute headways): Trains serve the less busy stations between SF and Redwood City every 30 minutes (possibly 15 during the peak), with a timed connection to Silicon Valley express trains at the latter. Reversing trains at Redwood City would be difficult however, and thus these trains should be extended to a new terminal at East Palo Alto (not pictured in the diagram). From there, the line could be extended via Dumbarton Rail to Newark, Fremont, and Union City (to be discussed in a future post). Remaining timeslots can be used on up to 4 high-speed rail trains to the Central Valley and Southern California (not pictured in the diagram).

Transfer at Hillsdale : Alternatively, all trains would run up and down the entire Caltrain corridor. During peak hours, three types of service would run, each on a 30-minute headway. Outside of peak hours, every station would receive local service on a 30-minute headway.

Caltrain Local : Makes all stops between SF and San Jose/Tamien, with a 3-minute stop at Hillsdale to allow express trains to pass. Total travel time – 1:16 / 1:21.

: Makes all stops between SF and San Jose/Tamien, with a 3-minute stop at Hillsdale to allow express trains to pass. Total travel time – 1:16 / 1:21. Silicon Valley Express : Makes all stops between San Jose/Tamien and Redwood City, then runs express to SF, stopping only at Hillsdale, San Mateo, Millbrae, and 22nd St. Total travel time – 1:05.

: Makes all stops between San Jose/Tamien and Redwood City, then runs express to SF, stopping only at Hillsdale, San Mateo, Millbrae, and 22nd St. Total travel time – 1:05. Baby Bullet : Limited express service between SJ and SF, stopping at Santa Clara, Sunnyvale, Mountain View, Palo Alto, Redwood City, Hillsdale, Millbrae, and 22nd St. Transfer to local trains at Hillsdale. Total travel time – 0:57.

Southbound Schedule:

Mission Bay 07:00 07:11 07:26 07:30 07:41 07:56 22nd Street 07:03 07:14 07:29 07:33 07:44 07:59 Bayshore 07:07 – – 07:37 – – So. San Francisco 07:12 – – 07:42 – – San Bruno 07:16 – – 07:46 – – Millbrae 07:19 07:26 07:41 07:49 07:56 08:11 Broadway 07:22 – – 07:52 – – Burlingame 07:24 – – 07:54 – – San Mateo 07:27 – 07:46 07:57 – 08:16 Hillsdale 07:31

07:34 07:34 07:50 08:01

08:04 08:04 08:20 Belmont 07:37 – – 08:07 – – San Carlos 07:39 – – 08:09 – – Redwood City 07:43 07:39 07:56 08:13 08:09 08:26 Menlo Park 07:47 – 08:00 08:17 – 08:30 Palo Alto 07:50 07:45 08:03 08:20 08:15 08:33 California Ave 07:52 – 08:06 08:22 – 08:36 San Antonio 07:56 – 08:10 08:26 – 08:40 Mountain View 07:59 07:52 08:13 08:29 08:22 08:43 Sunnyvale 08:03 07:56 08:17 08:33 08:26 08:47 Lawrence 08:06 – 08:21 08:36 – 08:51 Santa Clara 08:10 08:02 08:25 08:40 08:32 08:55 San Jose 08:16 08:08 08:31 08:46 08:38 09:01 Tamien 08:21 08:36 08:51 09:06

Northbound Schedule:

Tamien 07:18 07:36 07:48 08:06 San Jose 07:22 07:31 07:40 07:52 08:01 08:10 Santa Clara 07:28 07:36 07:45 07:58 08:06 08:15 Lawrence 07:32 – 07:49 08:02 – 08:19 Sunnyvale 07:35 07:42 07:53 08:05 08:12 08:23 Mountain View 07:39 07:46 07:57 08:09 08:16 08:27 San Antonio 07:42 – 08:00 08:12 – 08:30 California Ave 07:46 – 08:04 08:16 – 08:34 Palo Alto 07:49 07:53 08:07 08:19 08:23 08:37 Menlo Park 07:51 – 08:09 08:21 – 08:39 Redwood City 07:56 07:59 08:14 08:26 08:29 08:44 San Carlos 07:59 – – 08:29 – – Belmont 08:01 – – 08:31 – – Hillsdale 08:05

08:07 08:05 08:20 08:35

08:37 08:35 08:50 San Mateo 08:11 – 08:24 08:41 – 08:54 Burlingame 08:14 – – 08:44 – – Broadway 08:16 – – 08:46 – – Millbrae 08:19 08:12 08:29 08:49 08:42 08:59 San Bruno 08:22 – – 08:52 – – So. San Francisco 08:26 – – 08:56 – – Bayshore 08:31 – – 09:01 – – 22nd Street 08:35 08:24 08:41 09:05 08:54 09:11 Mission Bay 08:39 08:28 08:45 09:09 08:58 09:15

Expansion: Transbay Transit Center, Dumbarton Rail, and the Second Transbay Tube

While electrification is ongoing, Caltrain still has several projects in the pipeline. The next article of this series will examine Caltrain’s expansion plans to destinations such as Downtown SF, Fremont, and even Oakland. These Caltrain extensions would provide transfers to BART in the East Bay, creating a unified and integrated rail transit system for the Bay Area.