Capital Spending for Better Service

Wouldn't it be great if you could quantify the service benefit of capital improvements, to compare and prioritize them by how much better train service results?  We can, and using our handy Taktulator, we will. This service pattern evaluation tool was formulated around time-based service quality metrics. We use it to explore future improvements to the peninsula rail corridor.

Today's 2022 Timetable: 94 service points -- The current peak schedule with four diesel trains per hour features very generous padding and SF - SJ trip times ranging from 66 minutes (express) to 99 minutes (local). The less-than-100 score indicates that service quality has dropped since 2011 when there were five trains per peak hour. The Taktulator score is calibrated such that the 2011 Caltrain timetable scores exactly 100 points.

Caltrain's 2040 service vision foresees eight trains per peak hour per direction (not counting HSR). Let's start with a service frequency of 8 trains per hour-- except for the sake of exploring and quantifying the value of capital improvements, we'll start from a hypothetical case that will never happen: eight trains per hour of today's diesel service, making all local stops.

Hypothetical diesel all-stops local, 8 tph: Score = 109 service points (+16%) -- The doubling of hourly frequency improves the service score by 16%, despite each train being slower. The extra time riding an all-stops trains is more than offset by the much shorter wait time at the station. For example, maximum wait times in Belmont plummet from one hour to just 7.5 minutes. Unfortunately, this service pattern would take an unrealistic 32 trains to operate, because each train takes 94 minutes to go between SF and SJ. The hypothetical scenario still illustrates the magnitude of the effect of doubling frequency.

Add electrification: Score = 121 service points (+11%) -- Electrification is worth another +12 points relative to diesel, thanks to the shorter trip times that come from the higher acceleration capability of EMUs. Those savings accrue to a full ten minutes between SF and SJ for an all-stops local. Station dwell times are still booked at 45 seconds, a longer duration that reflects the lack of level boarding. Thanks to the faster trip times, the fleet requirement has dropped from 32 trains to 28 trains. Service speed saves money, not just on fleet size but also by increasing the hourly productivity of train crews (in terms of passenger-miles served).

Add Redwood City hub station: Score = 131 service points (+8%) -- If trains cannot pass each other, there is no room in such a frequent timetable for express service. A new four-track station at Redwood City, where express trains can overtake locals on opposite sides of the same station platform (so that passengers may transfer seamlessly between local and express) gives the best of both worlds: frequent service AND express service. For now, we'll assume this station has only two-track approaches, requiring trains to arrive and depart serially. In practice, this means every local must wait more than 5 minutes or the equivalent of two signal headways to let the express catch up before RWC and then pull ahead after RWC. The stopping patterns start to look like Caltrain's 2040 service vision.

Add Redwood City quadruple approach tracks: Score = 138 service points (+5%) -- If quadruple tracks are added approaching Redwood City from the north and south, then local and express trains can make parallel moves into and out of the hub station, removing the requirement for every local to wait there for five wasteful minutes. To unlock this benefit, the quadruple track overtake section needs to extend to one station on either side of RWC, so every local train can make productive use of those five minutes. In the Taktulator, we simulate this by having every local train stop at San Carlos and Atherton, which (despite its closure) stands in for a new Fair Oaks infill station at 5th Avenue. This suggests a hub station is about 1.7x more effective if it forms the center of a three-station quadruple track section. Having fully half your trains save five minutes is a huge service improvement!

Add level boarding: Score = 147 service points (+7%) -- Where electrification saved time in motion, level boarding saves time at rest by shaving 15 seconds of dwell time at each station, as step-free access smooths passenger boarding and alighting. Level boarding gives not only short dwell times but predictable dwell times (for example, wheelchairs don't take longer to board) so we can also tighten up the padding margin in the timetable, cut in this example from 12% to 7%. Interestingly, the end-to-end corridor times fall below a threshold that allows turning a train sooner, reducing fleet requirement from 28 to 24 trains. This isn't necessarily an effect of level boarding itself, and only illustrates that a series of small improvements can result in a discontinuous benefit when a certain threshold is reached.

Add SF Downtown Extension: Score = 250 service points (+70%) -- There are more jobs (over 100,000) located within a half mile of the Transbay Transit Center than there are jobs within a half mile of every other Caltrain station combined. This makes downtown SF a dominant node if added to the system, a fact that is reflected in our census-based weighting of available trips. No other improvement comes close.

Here is how these service improvements stack up against each other, plotted as the logarithm of the ratio of after/before scores, which gives you their relative impact. They can be constructed in a different order than imagined above, but the relative proportion of each improvement should remain approximately similar:

Bar graph of the relative service quality improvement of Caltrain capital projects

Here are some key takeaways:

1. Grade separation projects do not improve train service. Exceedingly rarely, they do prevent a train delay, something that is not captured in this analysis. On the basis of the time metrics of a typical trip, however, the service improvement of grade separations is ZERO. This should factor strongly into how many billions we are collectively willing to spend on them relative to the other capital improvements discussed here.
    
   
2. The benefits of electrification alone (without other improvements) are mediocre at best. On the basis of our time metrics, service quality is only improved by about 11% relative to an equivalent diesel scenario. Caltrain can't just finish the electrification project and call it good enough.
    
   
3. The Redwood City hub station now in the planning stages is surprisingly beneficial to service quality. While packaged and sold as a grade separation with a bonus of expanding the train station, it is hard to overstate the service quality benefit of the new hub station. Even as planned by Caltrain (with two-track approaches from the north and south) the new station produces nearly as much service improvement as the entire electrification project.
    
   
4. The Redwood City hub station as planned by Caltrain with two-track approaches is operationally ineffective. It can be juiced up to 1.7x more benefit to service quality by making it the center of a four-track overtake facility spanning just three stations: San Carlos, Redwood City and a new Fair Oaks infill station at 5th Ave. The southern portion of this four-track facility already exists today. Together with 4-track approaches, the Redwood City hub improves service quality by a greater proportion than the entire electrification project! That's why it is critical that planning for the Redwood City grade separations allow for four tracks throughout.
    
   
5. Level boarding provides over half the service quality improvement of electrification, and is likely to be a much cheaper capital investment. However, it makes sense to do it after the hub station.
    
   
6. The downtown extension in San Francisco will be a game changer for service quality. The transportation industrial complex knows this and will make us pay dearly for the DTX project. However, the additional billions for the PAX (Pennsylvania Avenue Extension, a city-desired grade separation) add absolutely nothing to service quality, and should never be allowed to be bundled with the DTX project. Every capital dollar should improve service quality.
    
   
7. The Redwood City hub station (with four tracks, not two!) is worth one fourth of the service benefit of the DTX. That means we should (a) not be shy about spending capital dollars to build it and (b) stop selling it as a grade separation, because that isn't the story here-- it should be about a new infill station, seamless transfers, and better service quality system-wide.
   

As always, the analysis provided here can be quibbled with and improved upon, and you are encouraged to "do your own research" by trying out your own service patterns in the Taktulator.

Risk and Opportunity in Redwood City

Lowe, a major real estate development firm, is preparing to redevelop Redwood City's Sequoia Station, an outdated strip mall adjacent to the Caltrain station, into a 12-acre mixed-use project with towers up to 17 stories tall.  If that is eye-opening to residents of Redwood City, consider that few people yet know that a greatly expanded Redwood City station is the keystone transfer node to enable the growth envisioned in Caltrain's business plan service vision. This new station will require slightly more land than the railroad already owns, and can only be located in Redwood City, the sweet spot that lies halfway between San Francisco and San Jose at the connection point to the Dumbarton rail corridor.

This creates a risk: if a commercial development project is allowed to proceed without respect to the future real estate needs of the railroad, then Caltrain will be constricted and unable to build the optimal infrastructure to support future growth.

Additional Land Needed For Caltrain

Caltrain and Samtrans have extensive land holdings at the Redwood City transit center. Still, just a bit more is needed to build a high-functioning piece of infrastructure, and be could traded for other parcels. Click to expand the map:

Land needed for future expanded station in Redwood City (shaded green)

Design Principles

The absolute worst way to build it.
Existence of this city rendering is
reason enough to be concerned.

To ensure that the Sequoia Station project becomes an exemplar transit-oriented development, rather than relegating Caltrain to the role of development-oriented transit, the rail agency and the developer should agree on some broad design principles.

• Think Big. Redwood City is one of the few stops on the peninsula rail corridor not surrounded by a sea of low-density single-family housing. Intensive land use and transportation must fit together to achieve a dynamic yet sustainable low-carbon future.
   
• Form follows function. No amount of architectural flourish or amenity can make up for a poor station design. Optimize for convenient access, easy transfers between trains and buses, short walks, direct and intuitive routes.
   
• Put the station at the center of the action, right over Broadway. Don't shove it to the north, out of the way of the development. The city rendering at right shows precisely what NOT to do.
   
• Configure the station as two island platforms to facilitate cross-platform transfers, without time-consuming vertical circulation or platform changes. The Caltrain business plan's staff-recommended service vision relies entirely on these Redwood City cross-platform transfers; every single train that pulls into Redwood City will make a timed transfer to another same-direction train docked at the opposite edge of the same platform. Denoting express tracks as 'F' for Fast and local tracks as 'S' for Slow, the optimal layout is FSSF with two islands, resulting in F-platform-SS-platform-F. Again, the city rendering shows precisely what NOT to do: passengers would not only have to change platforms, but also cross the tracks at grade.
   
• Elevate the train station to reconnect the street grid and make the railroad permeable to pedestrians, bikes, and other traffic. A busy four-track station is fundamentally incompatible with at-grade railroad crossings, and the only reasonable way to grade separate at this location is by elevating the entire station. Obstacles to pedestrian circulation such as the Jefferson Avenue underpass would be removed. Once again, the at-grade city rendering shows what NOT to do.
   
• Use four-track approaches from the north and the south. Cross-platform transfers are most efficient if trains do not have to arrive and depart sequentially using the same track, which adds about 3 minutes of delay. The best transfer is one where the two same-direction trains can arrive and depart simultaneously on their own separate tracks. Temporal separation is efficiently established by having the local train stop one station away from Redwood City (southbound at San Carlos or northbound at a new Fair Oaks station at Fifth Avenue) at each end of a new four-track segment that will ultimately measure four miles. In this arrangement, the express trains naturally gain on the local trains without a single passenger being delayed at Redwood City.
   
• Include turn-back tracks. Preserve room in the right of way north and south of the station for turn back pocket sidings, between the central slow tracks. Dumbarton rail corridor trains may not necessarily "interline" or continue on the peninsula rail corridor, so it's important to give them a convenient place to transfer and turn around without fouling other train traffic on the express tracks (hence FSSF arrangement). Same thing for a possible San Mateo local, which could serve the more densely spaced stops north of Redwood City.
   
• Don't be constrained by discrete city blocks. It could make sense to build structures or connect them over and across the tracks, more tightly knitting the station complex into surrounding mixed-use neighborhoods. This has some surmountable safety and liability implications, but buildings on top of busy stations are a common feature of successful cities around the world.
   
• Plan for long 400-meter platforms, not Caltrain's standard 700-foot platform length (again as seen in the city rendering of what NOT to do). While statewide high-speed rail plans currently do not include a stop in Redwood City, it is becoming enough of a destination and a regional transportation node that it makes sense to build a station large enough to future-proof it for service by long high-speed trains, regardless of what the California High-Speed Rail Authority might have to say about it.
   
• Think ahead about construction sequencing. Redwood City should be grade separated in one project from Whipple to Route 84, including the elevated station, taking advantage of Caltrain's land holdings to minimize the use of temporary tracks. A shoo-fly track would have to be built on Pennsylvania Avenue (within the railroad right of way) to make room for construction of the western two-track viaduct. Trains would begin using the elevated station while a second eastern two-track viaduct is constructed. Pennsylvania Avenue could re-open later, under the new four-track viaduct. Construction sequencing may drive how much extra land is needed for the railroad, so it's important to think it through up front.

If these design principles are respected, the re-development of Sequoia Station will present not a risk but an amazing opportunity to enhance Redwood City by realizing its full potential as the fulcrum of the Caltrain corridor and of a new regional express network reaching across the Dumbarton bridge and beyond.

Thinking Big in Redwood City

The architecture of Amsterdam Bijlmer
(photo by tataAnne) could represent
the future Redwood City station.

In a seamless transportation network that runs on a regular clockface schedule with timed, well-coordinated transfers, connecting nodes play a key role. Redwood City has natural potential as a connecting node, being located approximately at the midpoint of the peninsula rail corridor, serving as a logical transfer point between local and express trains, serving as the entry point to the peninsula from the future Dumbarton rail corridor, and being in of itself a significant destination with extensive connecting bus service and a willingness to grow.

With Redwood City currently renewing its interest in grade separations, it's important to think big and to re-imagine the station as a key node in the Bay Area's transportation network.

Start with a good timetable

Using our handy service pattern generator, let's see what we could do if we organized a blended system that made Redwood City a key transfer node. When you make a business plan, the first thing to be crystal clear about is: what is your product? In Caltrain's case, the timetable is the product, and all these stations and tracks should only be built as long as they contribute directly to delivering a quantifiably better timetable for the ordinary rider. Building a major new station in Redwood City isn't about trite superlatives like "Grand Central of the West," but simply about efficient and seamless coordination of timely and reliable ways to get from point A to point B.

Let's set some ground rules for our timetable:

• Caltrain expresses will operate every 10 minutes on a regular clockface schedule. A base 'takt' of 10 minutes reduces gracefully to 20 minutes or 30 minutes in the off-peak.
• In Silicon Valley, there will be no skip-stop service because the population and jobs are evenly sprawled. Every station in Silicon Valley needs to be served frequently, doing away with the ridership distortions induced by the Baby Bullet effect.
• In San Mateo county, where stop spacing is closer, slower local trains will operate every 20 minutes. These local trains will meet the express at Redwood City, before turning back north.
• Dumbarton service will operate every 20 minutes, meeting the express at Redwood City with little or no wait to transfer to trains on the peninsula corridor, before turning back towards the East Bay.
• Because the overall pattern repeats every 20 minutes, HSR will operate 3 trains per hour rather than the planned 4. Otherwise, there is a harmonic mismatch between the HSR frequency and the Caltrain frequency. 4 HSR trains per hour in a clockface timetable forces the base 'takt' to increase to 15 minutes, which is not desired.
• If we're going to make Redwood City a major node, it certainly rates HSR service, so we will create a new mid-peninsula stop for HSR.

This is the resulting timetable (see also additional data on service pattern), shown here for one hour in the southbound direction only (the northbound side is symmetrical). Colors denote the 10-minute Caltrain express, the San Mateo local, Dumbarton service, and HSR.

Notice the express arriving at Redwood City at 7:43 meets the Dumbarton train departing at 7:44, and the local arriving at Redwood City at 7:52 meets the next express at 7:53. Every ten minutes there is a cross-platform transfer, alternating between express-to-Dumbarton and local-to-express. Counting both directions, a cross-platform transfer occurs at Redwood City every five minutes!

Implicit in this timetable are a number of other capital improvements besides a new Redwood City station, such as overtake tracks in various locations along the corridor (highlighted in yellow in this view of the timetable... and while we're here, look how much less yellow is needed if HSR uses the Dumbarton corridor via Altamont Pass). It's important to remember that there is no formulation of the blended system that avoids the need for overtake tracks, unless one is willing to push slower trains into station sidings to sit for at least five minutes while a faster train catches up and pulls ahead. If you are a Caltrain rider, you should be wary of the cheapskates at the HSR authority who want to do this to your commute.

Deriving the functional requirements for the Redwood City node

To enable this timetable, we need the Redwood City station to have the following attributes:

1. Four platform tracks serving two 400-meter long island platforms to facilitate both northbound and southbound cross-platform transfers of very long, high-capacity trains.
    
2. Platforms centered on the best cross-town corridor, namely Broadway, for convenient access to and from local destinations on foot, by bike or scooter, by bus, or using the planned Broadway Streetcar.
    
3. A turnback track that enables certain Dumbarton corridor trains to originate and terminate in Redwood City, without fouling other train traffic, long enough for an EMU-8 train.
    
4. A turnback track that enables the San Mateo local to turn back in Redwood City, without fouling other train traffic, long enough for an EMU-8 train.
    
5. Elevated grade separation of all downtown Redwood City crossings, enabling free flow of pedestrians, bikes and vehicles under the rail corridor and including the re-connection of streets currently cut off by the existing configuration (e.g. Hopkins and James).
    
6. Bus facilities placed directly under the train platforms for seamless connections without the need for an umbrella. Same for an eventual Broadway Streetcar.
    
7. No mezzanine level. Mezzanines needlessly drive up the size and cost of stations, and impede and complicate vertical circulation. Street level can fulfill all the functions of a mezzanine, including ticket sales, wayfinding, waiting, retail, and dining.
    
8. The shortest and fastest possible vertical circulation (stairs, escalators, ramps, and elevators) using a U-shape viaduct cross section to avoid deep and vertical-space-wasting bridge structure. This helps with transferring quickly between the two island platforms, as would be needed for example to continue from the Dumbarton corridor south to Silicon Valley.

The footprint of such a station is not small. However, Redwood City has plentiful available railroad and transit district land, and the street level interface of such a station can be integrated into the city's street grid, opening up cross-corridor access and avoiding a wall effect. The aging Sequoia Station shopping center, with its wasteful surface parking, can be demolished and redeveloped to make room for an expanded station. Station parking can be moved underneath the approach structures, protected from the elements.

One possible station layout

An optimal station layout has four tracks, with the outer tracks for HSR and express commuter trains. The middle tracks are for commuter trains, and allow both northbound (Dumbarton) trains and southbound (San Mateo local) trains the opportunity to turn at Redwood City without impeding the flow of express traffic. The width of the structure is about 130 feet, as shown in the cross section below:

The northbound express track (Track 3) is tangent. The northbound island platform is 400 x 10 m. The center commuter tracks (Tracks 1 and 2) have curves that are not laid out in detail; this detail does not matter since any train that uses these tracks would slow and stop at Redwood City, using standard trackwork and turnouts. The southbound express track (Track 4) is the tricky one: it wows around the station, passing the southbound island platform on a 7500 m radius curve with approximately 1.5 inches of superelevation (not enough to matter for platform lateral tolerances). This track consists of a double reverse curve with six spiral transitions (tangent, spiral, curve, spiral, tangent, spiral, platform curve, spiral, tangent, spiral, curve, spiral, tangent). The curve is necessary to fit a pair of 400-meter island platforms (long enough to berth a double-length high-speed train) without bulldozing too much real estate.

Here is how this all fits (admittedly just barely) in downtown Redwood City:

The sacrificial victim is the Sequoia Station shopping center and associated surface parking crater, which can be redeveloped as part of the station complex with direct access from El Camino Real. Access for high-rise fire apparatus around the viaduct structure might also be a concern for the new condo buildings to the south, although this can be mitigated.

The station includes two pocket sidings to turn commuter trains. The siding south of the station can turn Caltrain locals at Redwood City, while the siding north of the station can turn Dumbarton service. Each siding is sized to store an eight-car EMU. Track center spacing is 15 feet throughout, and platform setback is 6 feet from track center. All viaducts are made from low-profile U-shaped sections that minimize the required height of the tracks and also double as sound walls, reducing the noise of up to 30 trains that would serve the station every peak hour.

Redwood City's slogan, "climate best by government test" would also become "transfer best" with timed, well-coordinated transfers to a variety of destinations. The impending start of designs for grade separations in Redwood City needs to factor in this future, and the city ought to think big.

Optimizing the Midline Overtake

The most important piece of infrastructure required for "blending" HSR with Caltrain on the peninsula rail corridor is an overtake facility, basically a several-mile long stretch of up to four tracks that will enable faster trains to overtake slower trains.  Caltrain studies have shown that the best performance (measured by robustness to cascading delays) can be achieved with a midline overtake  from San Mateo all the way through Redwood City.  Preliminary engineering and environmental clearance for this infrastructure is now resuming, with the recent award of a $36 million contract by the CHSRA to engineering firm HNTB.

The baseline configuration for this overtake is described in Caltrain's blended operations analysis, and assumes rebuilt stations at Hayward Park, Hillsdale, Belmont, San Carlos and Redwood City with four tracks and outside platforms in the tried and true style of the 1930s Pennsylvania Railroad. High-speed trains would use the center pair of tracks to overtake slower trains on the outside pair of tracks, as shown below (click figure to enlarge):

For comparison, the figure also shows a better solution that ensures the highest level of punctuality for all trains using the corridor.  This optimized overtake configuration differs from the baseline configuration as follows:

• The slow trains run in the middle, so that disruptions to local commuter service (for example, when an incident blocks a track for hours) do not disrupt high-speed service when commuter trains are re-routed around the incident location.  This track configuration is known as Fast-Slow-Slow-Fast (FSSF) as opposed to the traditional SFFS.  Real world examples of FSSF can be seen in train cab videos from Sweden and Australia.
   
• All commuter stations are built with central island platforms.  This allows commuter trains to use either platform face without confusing passengers, and requires only one set of station amenities (shelters, elevators, escalators, stairs, ticket vending machines, PA systems, train arrival screens, lighting, benches, etc.) because there is only one platform.
   
• A major new interchange station at Redwood City, with four platform tracks and additional train storage sidings.  This station (described below) would serve as a transfer point for HSR, Caltrain and future Dumbarton trains, as well as non-rail transportation modes.
   
• A carefully planned future-proofed high-speed rail junction where the Dumbarton rail corridor meets the peninsula rail corridor, preparing for the inevitable arrival of passenger rail service across the Bay.

Here's how it would ideally play out.

Short Term: the San Mateo Grade Separation

Preliminary rendering of new
Hillsdale station with island platform

The next step in the decadal process of grade separating the peninsula rail corridor will soon begin in San Mateo.  A new $180 million grade separation project is in the final stages of planning for 25th Avenue (currently a grade crossing) as well as 28th and 31st Avenues (currently not connected).  Concurrently with this project, the busy Hillsdale station will be moved a bit north of its current location and turned into an island platform.

This project is caught in an interesting political bind.  There is on one hand a rush to complete it by 2019 before Caltrain's electrification project, to minimize disruptions to Caltrain service.  On the other hand, due to its strategic location, this project will form a key building block of the blended system with HSR, which still needs to be environmentally cleared.  It is a near certainty that this portion of the corridor will require four tracks to enable trains to overtake each other, but any attempt to design and build it as such is likely to run afoul of HSR opponents who will accuse the CHSRA of advancing their project through CEQA piece-mealing.

The southern San Mateo grade separation design will have to be very carefully considered to preserve the ability to add two additional tracks with as little disruption as possible.  Road underpass profiles and bridge abutments should be designed for four tracks, as should the elevated structure that will support the tracks.

The choice of an island platform configuration for the new Hillsdale station is either a sneaky way to build a wide four-track embankment in preparation for yet another new station with SFFS outside platforms, or is an excellent choice for FSSF because it allows future tracks to be added without rebuilding the station for a second time.  One hopes the station access (stairs, ramps, etc.) will be designed to allow the platform height to be raised easily from 8" to 50".  An intelligently designed San Mateo grade separation would atone for the terrible failures of the San Bruno grade separation, designed with great hostility towards higher speeds or additional tracks.

Medium Term: Redwood City HSR Station

Amsterdam Bijlmer (photo by tataAnne)
could just as well be the future
Redwood City train station.

While the CHSRA's plans for a mid-peninsula stop have been shrouded with ambiguity for several years, Redwood City stands out as a more optimal location for a new HSR station than Palo Alto or Mountain View, the other two locations in the running.  Unlike its neighbors to the south, Redwood City favors strong urban growth, has a large amount of railroad land available, and is reasonably well-connected to the existing road and transit network.  Redeveloping the antiquated but popular Sequoia Station shopping center would enable the construction of an elevated four-track station with plenty of capacity to support not just HSR but also Caltrain cross-platform connections and future Dumbarton service.

The station complex would feature two shared (HSR or Caltrain) 400-meter island platforms centered between Broadway and Brewster, easily accessible from both streets.  Bus connections would be conveniently located under the station. To the north of the platforms, a pocket turnback track would allow Dumbarton trains to reverse without fouling other traffic.  Similarly, to the south of the platforms, another pocket turnback track would allow southbound Caltrain locals to terminate in Redwood City before turning northwards again to serve the densely-spaced stations of San Mateo County, allowing Caltrain to serve more passengers with fewer trains and crews.  Thanks to the FSSF configuration, all this to-and-fro by commuter trains would stay well out of the way of HSR.

This would be a large train station and quite a tight fit (if you're curious about exactly how large and how tight, download this KML file into Google Earth to view the station footprint and track layout).  It would be a big change for Redwood City, but with a huge payoff: the tracks would no longer form a barrier through town, and the Sequoia Station shopping center would be merged with the station to form a gateway and a destination in its own right that is connected to downtown.  HSR service could make the city a very desirable location for business.  The new station could become the centerpiece of the ambitious revitalization strategy described in Redwood City's downtown precise plan.  But this idea is not without pitfalls, as the size of the station could be compared to plonking a couple of Nimitz-class aircraft carriers in the middle of town.  To use the tired slogan, it needs to be done right.

Medium Term: a New Fair Oaks Station

Approximate location of new Fair Oaks
station island platform, view to northeast.
Overtake would extend just beyond
platform to the right (south).

The key to reliable overtaking on a multiple-track railroad is to ensure that the average speed of the slower train being overtaken is sufficiently slower than the average speed of the faster overtaking train.  One of the ways of ensuring a good speed differential is to have the slower train make station stops that the faster train doesn't; each station stop is worth about 2.5 minutes.  Therefore, locating stations on the four-track overtake section is helpful.

This brings us to a lemon of a station immediately south of the midline overtake: Atherton.  Located in an area of very sparse population and jobs density, Atherton should be permanently closed.  This closure would come not only as a show of appreciation commensurate with the town's support of Caltrain modernization, but especially because census data shows clearly that Atherton is precisely where you would never place a train station.

To replace Atherton, a new Fair Oaks station should be built just 0.6 miles to the north, at the 5th Avenue grade separation.  The overtake section would be extended a bit southwards, just beyond the station, enabling locals to be passed while stopped at the central island platform that can be accessed from either side of 5th Avenue.  The new Fair Oaks stop would be equidistant from Redwood City and Menlo Park, and located in an area with very high population density that could support thriving ridership, in contrast to Atherton.

Longer Term: a Seamless Dumbarton Connection

Dumbarton rail has been an uncertain prospect for decades, with some political backing but insufficient funding.  While it may take another few decades for the money and the will to finally materialize, large concentrations of employment and the need for additional transbay corridor capacity make some form of passenger rail service inevitable.  The Dumbarton corridor also happens to be ideally suited for high-speed rail.

The key node is Dumbarton Junction, which should be reconfigured in such a way that trains can enter and leave the peninsula rail corridor swiftly and seamlessly.  This will likely involve a flyover track, enabling southbound trains to enter the Dumbarton corridor without crossing (and therefore blocking) any of the northbound tracks.  To minimize the altitude of the flyover, the Rte 84 / Woodside Road overpass would be turned into an underpass.  As for the Redwood City station, the fit would be quite tight with a 90-foot corridor width where the flyover track begins.

While the flyover may seem like an expensive solution to a problem we don't yet have, planning for it now (if not actually building it) will save money in the long run when passenger rail service grows.

Design Values

No matter how the midline overtake is ultimately configured, it must reflect design values that are clearly articulated.  One of these values should be compatibility between Caltrain and HSR.  It's not enough to talk about the "blended system" without actually taking the steps to make the two systems seamlessly interoperable, allowing any train to use any track to serve any platform.  This means no tracks can be dedicated to one operator at the exclusion of another.  Everything must be shared, including the platforms at the new mid-peninsula station.  This sharing contributes to another important value, robustness to service disruptions.  The fast-slow-slow-fast track layout is the key to ensuring that a commuter train delayed in Belmont won't create a statewide domino effect that eventually makes a train late in Los Angeles.  A third important value is future-proofing.  Infrastructure like the midline overtake will define what is possible (and not) for generations to come.  It would be short-sighted not to plan for a fast and seamless connection to the Dumbarton corridor, even if its future use isn't well-defined today.

The midline overtake is the key to an effective blended system.  When evaluating its design, ask yourself: is it compatible?  Is it robust?  Is it future-proof?

Census Driven Service Planning

The diagram at right shows where people live and work along the entire length of the rail corridor from San Francisco to Gilroy, as extracted from government census population and jobs data sets.  The diagram is also available as a PDF.

Implications for Rail Service Patterns

By simple observation of the features of the census population and job distributions along the peninsula corridor, it is possible to infer the desirable features of train service patterns that will maximize commute ridership.

1. Transbay has more than 100,000 jobs within a half-mile radius (more than every other station in the system combined). The concentration of jobs near San Francisco's Transbay Transit Center cannot be understated. This station absolutely must be served by each and every train, and it would be highly counter-productive to terminate any train at 4th and King.
    
2. Silicon Valley shows up in the jobs distribution as a broad hump, mostly homogeneous and stretching from Palo Alto to San Jose.  To serve this rich but diffuse commute market, all trains should make every stop in Santa Clara County.  There should never be any skip-stop service here, and the wider spacing of stops (relative to San Mateo County) will result in only minor trip time penalties.
    
3. San Mateo County has numerous stops, spaced more closely together and with middling jobs and population density.  To enable faster service to and from San Francisco and Silicon Valley, it makes the most sense in this portion of the corridor to operate skip-stop express service alongside local service.
    
4. South San Jose, while south of Silicon Valley, has a massive and untapped residential market that can serve as origin to jobs further north.  Tamien currently functions as a slow and infrequent addendum to the peninsula service, but should be sped up and extended to Blossom Hill.
    
5. Oakdale in San Francisco opens up a new residential market for Caltrain.  The distribution of people nearby is even denser than at 22nd Street.
    
6. The Gilroy extension doesn't make much sense.  There are so few jobs and people here that Caltrain (as primarily a commuter service) should not run to this area.  Serving Morgan Hill and Gilroy is best left for a long-distance operator such as Amtrak California.

Putting all this together, what would a service pattern look like that is tailored to the census distributions, to maximize commuter ridership?  First, it would not look like today's Baby Bullet, which severely under-serves numerous stops.  It would also look very different from Caltrain's latest planning fad, the "peak-period skip-stop zone express," used as the basis for all operational simulations in the blended service analyses published to date.  It would look like this, with distances drawn to scale:

• The Silicon Valley express links the major employment centers of San Francisco and Silicon Valley, highlighted in orange, providing a faster and better alternative to fleets of white luxury buses stuck in traffic on US 101.  It would run every 15 minutes.
   
• The San Mateo local serves all the minor stops throughout San Mateo County, terminating and originating across the platform from the Silicon Valley express at Redwood City.  This provides fast and penalty-free transfers between Silicon Valley and cities all along the peninsula.  The local turns back in Redwood City, minimizing crew and fleet requirements while still providing service every 30 minutes.
   
• Stops in San Francisco and San Jose that have very large residential markets are served in the peak commute direction only.

This service pattern is also well-suited to future blended HSR service: a southbound high-speed train and a closely-following Silicon Valley Express can overtake and catch up (respectively) with a San Mateo local by using a four-track mid-line overtake facility constructed from San Mateo to Redwood City.  Because the local turns back at Redwood City, it does not impede traffic in Santa Clara County.

The time has come to fundamentally rethink peninsula rail service patterns.  Caltrain's "peak-period skip-stop zone express" is almost certainly not the best solution for meeting future demand; a much wider range of options must be considered.

Station Design 101

If you're the poor sucker in charge of designing a mid-peninsula high-speed rail station, here's what you must do: start with the ridership estimates for full 2035 system build-out, and apply Technical Memo 2.2.2 (station design policy) as handed down from above by Parsons Brinckerhoff, the firm in charge of the HSR system design. Table 6.1 has all the relevant formulas that you'll need to size the outer concourse, controlled waiting areas, how many restrooms, etc. All that remains is to plug and chug the formulas and presto, you've got yourself a station.

The result of this formulaic approach to station design can be seen in the recent sizing study for a potential mid-peninsula station at Mountain View, which is very similar to the notions also being entertained for Palo Alto or Redwood City. Key statistics: about 8000 daily HSR boardings, 67000 square feet of floor area (not including platforms), and 3000 parking spaces.

Implicit Requirements

While the technical policy and system requirements do contain a variety of clearly stated requirements concerning station design, many of the requirements are not stated, but instead taken for granted. They are implicit requirements. The following is an attempt to make them explicit:

• The station shall funnel every passenger through a sequence of functional spaces that broadly mimic an airport.
  
  
• The station shall be divided into a public concourse and an access-controlled area requiring possession of a valid ticket.
  


• The station shall have a mezzanine, a large access concourse located above or below the platforms that provides the "necessary" floor area to funnel passengers from a grand station entrance (complete with "entry plaza") through "check-in", shops and restaurants, and possibly "security" to a "gate".
  
  
• The HSR platforms shall be used exclusively by high speed trains, and may not under any circumstance be shared with Caltrain. The same track and platform edge may not be served by both HSR and Caltrain. The same platform at opposite platform edges may not be served by both HSR and Caltrain.
  
  
• The HSR platforms shall be fully access controlled with high fences, even if such fence is used to segregate the HSR platform from an adjacent Caltrain platform.
  
  
• Passengers transferring between HSR and Caltrain shall use escalators and transit via the mezzanine. Maximum vertical circulation is encouraged, and convenient cross-platform or same-platform transfers are explicitly disallowed.
  
  
• The station shall have gargantuan amounts of automobile parking (1000 spaces at the station, and another 2000 spaces within 3 miles).

None of these "requirements" make any sense, except to maximize the size and cost (and profit) of building such grandiose but operationally dismal infrastructure. What is being envisioned here is not an integrated rail network, but well and truly a flight-level zero airline.

Another Way

It doesn't have to be this way. In France or Germany, any bum off the street can drag a large suitcase onto a high-speed train five minutes before departure without ever passing through a security check or a fare gate. Tickets are checked on board, using what's known as proof-of-payment or POP: if you can't produce a valid ticket when asked, you are issued a citation. POP obviates all this sterile-area gated fare-paid-only nonsense, with enormous simplification of the process of getting from point A to point B.

Is POP a gaping security hole? Not if you consider that bombs brought on board high-speed trains are a rather unreliable way to achieve mass carnage. That's why over several decades, such an attack has only been carried out once, and then rather unsuccessfully. The target environment will necessarily be far richer over on the Caltrain platform. Terrorists in Madrid knew this when they attacked at Madrid's main HSR terminal; all their bombs went off on packed commuter trains. So, a rational evaluation of threats (one not based on security theater) leads to the conclusion that HSR need not look like a BART fortress on steroids.

In Europe, land of POP, commuter rail and HSR routinely share platforms, leading to far more efficient use of space inside stations. For example: Paris, Berlin, Karlsruhe, Hamburg (on a sacrilegious curved platform, no less!), Brussels, and dozens more.

The graphic below shows the differences between the gargantuan mid-peninsula dial-a-station proposed by the CHSRA (and rightly rejected by Mountain View, Palo Alto and Redwood City) and a mid-peninsula station of far more modest proportions, that could be achieved without any loss of functionality provided that the following simple requirements are adopted:

• HSR shall use barrier-free fare control
  
• Caltrain shall use the same platform height as HSR
• Stations shall allow any train to use any track to access any platform
  
• Stations shall minimize vertical and horizontal circulation needed to access any train

Appropriate station design requirements have an enormous effect on the resulting designs, with overall width dropping from an elephantine 265 feet (as depicted in the sizing study) to a more manageable 122 feet.

At a time when the HSR project is increasingly under attack for being insensitive to peninsula communities, perhaps a reevaluation of station requirements would improve the chances of someday achieving a context-sensitive solution. Mountain View, for example, could have the highly-effective, low-impact intermodal station previously described in this space.

Alternatives Analysis Analysis, Part 2

If you haven't run out of steam as you finally reach Appendix K of the recently-released preliminary alternatives analysis, you will come across an intriguing fact: by the year 2025, Caltrain plans for a best trip time of 65 minutes from San Jose to San Francisco 4th & King, and 70 minutes to the Transbay Transit Center.

The Baby Bullet we know and love does San Jose to San Francisco in as little as 57 minutes (by the timetable, which is generously padded at the end of the run to make on-time performance statistics look better). In practice, diesel bullets can and do make the run in 55 minutes.

How can this possibly be? $6 billion later the best commuter service will be 10 minutes slower?!?

How can a timetable, the very root of years of painstaking planning and carefully apportioned capital investment, the embodiment of a grand vision of improved commuter service, the next coming of the Baby Bullet, fall so terribly short of what could have been?

How many microseconds will it take for the entire NIMBY universe to latch on to this inconvenient truth?

Some observations:

• The proposed timetable, towards which every Caltrain capital investment ought to be targeted in tangible and measurable ways, is presented almost apologetically, and seems almost an afterthought;
  
  
• Caltrain plans to give up (that's right, give up!) commuter trains overtaking each other, despite the presence of a third and fourth track in what is nominally a "shared corridor", and henceforth operate on just two tracks. The reason offered is that overtakes are operationally unreliable--but that is only so because Caltrain's existing passing tracks are very short, and Caltrain's existing gallery cars turn station dwell times into a game of Russian roulette. By 2025 both of those reasons will have vanished.
  
  
• Confining Caltrain to a separate, 2-track system does not take advantage of any synergy with HSR, and perpetuates a false choice between speed and frequency. Today this trade-off is biased in favor of speed, but the Baby Bullet limits throughput to 5 trains per hour. In Caltrain's proposed 2025 timetable, based on the BART model, the trade-off is biased in favor of throughput (one train every six minutes!) but average speed suffers just like BART's. In a fully HSR-compatible system with a mid-line overtake, this constrained trade-off would be removed entirely, freeing Caltrain to provide both speedy AND frequent service with cross-platform transfers.
  
  
• The underlying assumption appears to be that with HSR in the mix, Caltrain will no longer need to provide express commuter service. Even as Caltrain is starved of operating funds and teeters on the brink of bankruptcy, it appears perfectly willing to cede its highest-yielding ridership to the HSR operator, with no guarantee that service will mesh together with convenient timed transfers and a common fare structure.
  
  
• Some might say, if there will be a high-speed train every five minutes in each direction, how could there possibly be any spare track capacity to allow Caltrain to overtake on the high-speed tracks? This question is ill-posed: a portion of that ridiculously frequent HSR service would no doubt be used to serve intra-peninsula demand that Caltrain could not tap into if it were stuck on two tracks with slower trip times. The track capacity should be re-allocated to better meet demand.
  
  
• The fundamental issue here is one of flexible and dynamic allocation of a scarce and valuable resource: track capacity. If you build two separate systems that are not designed to inter-operate (freely sharing tracks and stations), then you cannot adjust service patterns to meet the demand that actually develops. You're stuck with guessing what demand will be 25 years from now, and quite literally casting it in concrete. The outcome, more likely than not, is sub-optimal, with demand under-served and resources under-used.

Caltrain's entire strategic service plan ought to be re-oriented toward the following specific interoperability goals:

• The same platform height as HSR, so station platforms can be allocated to actual demand, making optimal use of a scarce resource;
• The same train control system as HSR, so commuter trains and high-speed rail can freely mix and track capacity can be dynamically allocated to actual demand, again making optimal use of a scarce resource;
• An improved timetable that provides both speed AND frequency through the implementation of a mid-line cross-platform overtake.
  

With those features, a good case could finally be made that the high-speed rail project would produce tangible benefits that trickle down in measurable ways to each and every community along the peninsula rail corridor. Sadly, right now it looks like those $6 billion will buy us 10-minute slower commuter service. This is simply unacceptable.

The Tao of Timetables

Amid all the hoopla about high-speed rail and quadruple tracking on the peninsula corridor, it's easy to miss the original point: to convey people from point A to point B as quickly and conveniently as possible. The peninsula rail improvements aren't just about pouring concrete and running zoomy trains; they ought to be about providing a service, especially to the dominant users of the corridor, namely local commuters and travelers, people who live and work right here on the peninsula. This important constituency is too often eclipsed by the bright spotlight shining on statewide high-speed rail.

Service is where it all begins, as demonstrated when Caltrain's Baby Bullet started operating in 2004. Because the Bullet increased speed and convenience, ridership soon grew by a third, and Caltrain was featured on the cover of industry journals. But the Baby Bullet was just a baby step compared to what might soon be possible, and Caltrain can't afford to rest on its laurels.

The only three things that will really matter for the future of Caltrain are service, service and service.

(photo by Christophe Dune)

Constructing the Ideal Caltrain Timetable

Timetables are admittedly boring, but they are a compact and efficient way to describe a transit service. Improvements to the service are best understood through their effect on the timetable. Caltrain passengers stand to benefit from several future service improvements that can be sorted into two categories: (a) service improvements that come "for free" as a result of electrification and swift new EMU trains, and perhaps more importantly (b) service improvements that require a little bit of planning, creativity, intelligence, and effort to pull off.

Caltrain is relentlessly focused on (a) and appears distressingly oblivious to (b).

Type (a) service improvements that can basically be taken for granted are:

1. Quicker start-to-stop times, since EMUs are more powerful and lighter than today's anemic and heavy diesel trains. The time savings from faster acceleration and braking really accrue when a train makes many stops.
   
   
2. Shorter station dwell times, since EMUs will have more doors and level-boarding for rapid passenger loading and unloading.
   
   
3. Faster top speeds, since the peninsula corridor will be grade-separated and use a modern signalling system shared with HSR. While acceleration is far more important than top speed, improving from today's 79 mph speed limit to about 100 mph does yield marginal benefits.
   

Those are very nice, but they're just the low-hanging fruit. Type (b) service improvements are less obvious, but deliver enormous benefits for passengers. They include:

1. Clockface scheduling, known in german-speaking countries as Taktverkehr (literally, "traffic to a beat"). In a clockface schedule, every train runs on a periodic timetable with a regular stopping pattern that repeats at some fraction or multiple of an hour (e.g. every 15, 30 or 60 minutes). In Switzerland, the entire country runs on a regular beat. Clockface scheduling eliminates annoying Caltrain questions such as "When is the next train coming?" or "Does it stop where I'm going?" A clockface schedule takes all the guesswork out of taking the train by allowing simple memorization of the timetable (e.g. :07 past the hour, every 15 minutes) Clockface scheduling is also a key enabler of intermodal connections. Connecting feeder services, whether bus, employee shuttle, light rail, HSR, etc. can be synchronized to the "beat" for quick, hassle-free transfers.
   
   
2. Zero-wait transfers between local and express trains, so customers at smaller station stops can benefit from fast express service to the destination of their choice. Zero-wait transfers extend the benefit of express service to a much wider selection of origin and destination pairs. A zero-wait transfer means that an express train overtakes a local at zero speed, on the opposite side of the same platform. Passengers simply walk across the platform to switch to a faster or slower train, as suits their destination. Overtaking at zero-speed enables such transfers in the first place; if one were to wait for the express, the time savings from the express would evaporate before they could provide any benefit.
   
   
3. Two, or maximum three, station stopping patterns, for simplicity. Customers no longer fret whether any given train will stop at their destination; no more agonizing Caltrain questions like "Should I get on this train or the next?" or "Does this train serve the stop where I'm going?," no more squinting at the timetable. Caltrain conductors would no longer make long-winded and repetitive announcements about upcoming stops and which stations will or won't be skipped.
   

What would an ideal Caltrain timetable look like with all of these improvements? We'll soon find out, but first, a small detour through...

String Theory

To think about timetables without having to stare at big tables of numbers, it helps to use a graphical representation of rail traffic known as a string graph (also known as a stringline diagram). Traffic is displayed as a time-distance graph with time along one axis and stations (distance) along the other. The movement of each train is represented by a string that connects each station according to the time intervals required to move from one station to the next. In effect, a string graph is the visual equivalent of a timetable. For example, the weekday morning Caltrain timetable is shown in the string graph at right. There are many kinds of strings, each corresponding to a different stopping pattern; the irregular pattern makes it difficult to memorize the timetable between any two stations. The red strings represent Baby Bullet express traffic, and the blue strings represent slower trains. When the lines cross (as circled on the diagram), one train overtakes the other. Today this can only happen in Sunnyvale or Brisbane, where Caltrain already has four tracks.

Going back to our list of ideal timetable features, we can construct a string graph that includes them all. In the real world of operations planning, this is done using sophisticated simulation software, and needs to take into account detailed train performance, speed limits, curves, signal block lengths, off-nominal conditions, and knitting together with the HSR timetable (itself a complicated mess; see pages 16-24).

To first order, it can be done with a spreadsheet. Download a Caltrain string graph (385 kB Excel spreadsheet) to play with it.

The resulting Caltrain timetable is shown in the string graph at right, screen-grabbed directly from the spreadsheet. This string graph shows an example timetable, at a relatively sparse 6 trains per hour, with the following features:

• 15-minute local interval
• 30-minute express interval
  
• Fast acceleration using 90 mph EMUs
• 45-second platform dwell times
• Zero-speed cross-platform overtake at Redwood City

It's quite easy to change these assumptions using the spreadsheet to see what happens. At a glance, the timetable certainly looks more symmetrical and orderly, but how does one meaningfully compare old and new?

The Service Improvement Table

The best way to convey an improvement plan in a way that the average person understands is to publish a service improvement table, an example of which is shown at right. (This example table does not show every station pair; for brevity, it shows a sampling of 10 stations.) This table is built by simply comparing the old and new string graphs. For each station pair along the peninsula, the improvement table shows how many more trains per hour connect the station pair, and how much quicker they are than today. This table is constructed by comparing the string graph of today's timetable with the string graph we constructed above.

The table is a quantitative, objective measure of the degree to which service is improved. All capital improvements on the peninsula corridor should be evaluated and prioritized by their effect on the service improvement table.

Marketing 101

Memo to Caltrain: nobody really cares about "growth" or "advanced technology" or "flexible equipment" or "power facilities", or even "less pollution" as trumpeted in the latest electrification update. Those are entirely the wrong selling points. What customers most care about is getting quickly and conveniently from point A to point B.

Damn the pantographs, what you need to sell and deliver is a service plan.

When people ask "what's in it for me", show them the service improvement table for where they live and work. When people worry about the disruption from the peninsula HSR project, they can see that some benefits actually trickle down meaningfully and measurably to each and every city along the Caltrain corridor. Put this table in front of city council members up and down the peninsula. Publish it in local newspapers. Make brochures. Drop leaflets. When Burlingame gets worked up about grade separations, explain to them that service at Broadway will go from none at all to a train every 15 minutes. When Palo Alto frets about community division, show them how California Avenue will see a quadrupling of service, and will be 9 minutes closer to Millbrae.

A Litmus Test

The dirty little secret is that all the service improvements described above could have been realized without HSR, requiring only a few miles of strategically placed track amplification to enable a mid-peninsula overtake, and using capital improvement funds in a targeted fashion that measurably improves service. (Instead, Caltrain is plowing $300 million into the San Bruno grade separation, which provides zero service improvement, while claiming it is fiscally doomed without HSR).

The peninsula HSR project, which continues to be engineered for extremely high levels of service (despite lowered ridership estimates), will consume precious resources that currently belong to Caltrain--in particular, key portions of its corridor. Constructing HSR in a manner that precludes the above schedule, or something similar to it (i.e. clockface schedules with mid-line overtakes) from being reliably operated will forever stunt the future of the peninsula commute. That can rightly be considered totally unacceptable.

The timetabling criteria outlined in this article form an objective litmus test for an important question that should linger in the minds of peninsula residents: MOU notwithstanding, is Caltrain getting screwed over by the HSR project? Armed with this knowledge, you can be the judge.