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?

Primarily Two Tracks

Figure 4 from Caltrain's study, showing several possible locations for new overtake tracks.  Not all would be built.

In recent days, the high-speed rail Draft Revised 2012 Business Plan as well as the Caltrain Blended Operations Analysis were released to the public.  Both of these documents refer to the peninsula blended solution as a "primarily two-track" system, in the hope of allaying fears of massive eminent domain takings of homes and business-- fears that are largely unfounded, but fanned relentlessly by the local press and project opponents.

The confusion continues over what "primarily two tracks" precisely means, because neither agency seems ready to come out yet and state it in crystal clear terms.  The process still needs to unfold.  Luckily, enough data has already been published to allow a reasonably good reading of the tea leaves, down to the nearest tenth of a mile.

Phase 1 will be electrification, according to the memorandum of understanding currently being put in place by MTC and other parties.  This project already has federal environmental clearance and is very close to state environmental clearance, although a strong push will be made by opponents to subsume Caltrain's electrification EIR into the peninsula HSR project EIR, a document that will not be finalized (let alone litigated!) until 2015.  This phase of the project will not add any tracks, so the total length of quadruple track will stay as it is today (2 miles in Brisbane; 1 mile in Redwood City; 2 miles in Sunnyvale).

• Purpose: improves Caltrain, enables future peninsula HSR
• Time frame: 2013 - 2019
• Total miles of quadruple track: 5
• Grade-separated fraction: 61% (64 of 104 road crossings)
• Trains per peak hour per direction: 6
• Cities impacted by construction: none

Phase 2 will be a concrete viaduct through Santa Clara, completed at the same time as HSR reaches San Jose sometime in the mid-2020's, enabling a one-seat ride to San Francisco under the so-called "Bay-to-Basin" scenario.  If the CHSRA's grandiose plans (described in an October 2011 report to the legislature) are to be believed, this will entail building a massive double-decker station complex at San Jose.  A new four-track HSR station will hulk over the existing Diridon Station, perched on massive concrete straddle bents.  A more than 3-mile-long, 60-foot-tall viaduct will be constructed northwards, joining the existing corridor at approximately milepost 44.5, north of the Santa Clara Caltrain station.  Overpasses at Hedding and De La Cruz will be demolished and rebuilt as underpasses to make room for the new double-deck rail right of way.  Note that Caltrain's study considers this phase as part of the "baseline infrastructure" and therefore does not count it as additional tracks.

• Purpose: enable single-seat HSR ride to San Francisco
• Time frame: mid 2020's
• Total miles of quadruple track: 8
• Grade-separated fraction: 61% (64 of 104 road crossings) 
  
• Trains per peak hour per direction: 8 (6 Caltrain + 2 HSR)
• Cities impacted by construction: Santa Clara

Phase 3 will be the "short" mid-line overtake from 9th Ave in San Mateo (milepost 18.3) to Whipple Ave in Redwood City (milepost 24.8), which enables HSR service to increase from 2 to 4 trains per hour during the peak.  The data tables in Caltrain's study show that this overtake facility provides nearly all the benefits of the "full" mid-line overtake that extends southwards through Redwood City, but presumably at far lower cost.  The transportation-industrial complex's approach to the short mid-line overtake might very well entail demolishing the entire Belmont - San Carlos grade separation and replacing it with a four-track viaduct on concrete stilts.  A more realistic implementation will likely be to tack on another 15 feet of width on each side of the existing grade separations to accommodate new overtake tracks, something that should have been done in 1999 (but why do it right when you can do it twice?).  In San Mateo, new four-track grade separations will be built at 25th, 28th and 31st Avenues.

• Purpose: increases HSR peak capacity from 2 to 4 trains per hour per direction
• Time frame: late 2020's
• Total miles of quadruple track: 14.5
• Grade-separated fraction: 63% (67 of 106 road crossings) 
  
• Trains per peak hour per direction: 10 (6 Caltrain + 4 HSR)
• Cities impacted by construction: San Mateo, Belmont, San Carlos

Phase 4 will be the "full" mid-line overtake, also known as the Great Redwood City Grade Separation, creating a new mid-peninsula HSR stop at Redwood City and grade-separating a dense cluster of six grade crossings.  The four-track mid-line overtake will be extended southwards to milepost 26.3, merging with the existing four-track section.

• Purpose: adds mid-peninsula HSR stop
• Time frame: late 2020's
• Total miles of quadruple track: 16
• Grade-separated fraction: 69% (73 of 106 road crossings) 
  
• Trains per peak hour per direction: 10 (6 Caltrain + 4 HSR)
• Cities impacted by construction: Redwood City 

Beyond that, it gets murkier.  Presumably, the 33 remaining grade crossings that are not removed under Phases 1 - 4 will be addressed on a case-by-case basis, with grade separations designed and built in consultation with the respective cities.  San Francisco's downtown extension to the Transbay Transit Center may finally be built.  Additional passing tracks may be constructed where it's relatively easy and cheap, for example the remaining 2.5 miles from Lawrence to Santa Clara and the "north overtake" in Caltrain's study, an additional 8.2 miles of quadruple track from Brisbane south into Burlingame.

Only one thing is quite certain: the peninsula rail corridor will categorically NOT remain a two-track operation, even if it might still use "primarily" two tracks.  At a minimum, approximately 16 miles or over a third of its length will be quadruple-tracked.  As the process unfolds, it will become apparent that the cities of Belmont, Redwood City, San Carlos, San Mateo and Santa Clara will be the first to suffer the construction impacts.

Development Oriented Transit

In San Carlos, plans are afoot to build a so-called "Transit Village" on a strip of vacant land adjacent to the train station. The land, owned by Caltrain and SamTrans, the county transit agency, was acquired for construction of the grade-separated berm (see Focus on San Carlos).

The Draft EIR for the Transit Village project is currently open for public comment.

The plans are remarkable for their amazing lack of coordination with the high-speed rail project. The Transit Village FAQ dismisses the issue in one fell swoop:

How will the project affect the proposed high speed rail service?
The project will not affect the proposed high speed rail service because the project site design already incorporates the necessary space for the future high speed rail service.

A recent article in the San Mateo Daily Journal, highlighting concerns about the project, failed to mention the high-speed rail issue even once.

Meanwhile, HNTB, the engineering firm in charge of the peninsula rail corridor, is actively considering several design alternatives that would widen the corridor to well over 100 feet at the San Carlos station. One of these alternatives is to run a pair of HSR tracks west of the existing station, right where the Transit Village buildings are planned. Perhaps this is a game of who gets there first, but no matter which way you slice it, four tracks plus platforms are going to exceed 100 feet in width.

The project EIR includes several site sections, an example of which is reproduced above superimposed with one of the HSR configurations currently under consideration. (Click for the complete diagram, drawn to scale, without any utility easements--i.e. as narrow as possible). If the railroad right of way is not expanded eastward into Old County Road and the adjoining East San Carlos neighborhood, then the required rail corridor will quite literally overlap with the planned buildings as shown in the figure. Short of an actual overlap, even close proximity would be unacceptable from an interior noise standpoint, and would preclude emergency vehicle access to the rear of the buildings. The inescapable conclusion:

The project will very much be affected by HSR, quite possibly up to eminent domain and demolition.

Anyone who says otherwise is trying to sell you a Transit Village. Who will pay for this egregious lack of foresight? Probably the suckers who buy the residential units, and the suckers who pay taxes to fund needlessly expensive right-of-way acquisition. Remember, this little soap opera will take place on land that is currently owned by Caltrain and SamTrans!

Why pull another San Mateo? Have Caltrain and SamTrans learned nothing about sacrificing valuable railroad right-of-way on the altar of cities' pet projects? Is somebody in Sacramento going to wake up and knock some heads together? Or is it on us to foot the bill after the mess is made?

Some Light Reading

UPDATE 2: San Carlos has also posted their draft scoping comments for their city council meeting of Monday 2/23. The letter includes a concern about vertical clearances at the Holly St. underpass, which the Daily News (Redwood City edition) quickly blew out of proportion by proclaiming: Major High Speed Rail Dilemma Discovered in San Carlos. If that is the biggest problem we have on the peninsula, the high speed rail project really must be in great shape! This area is smack in the middle of the future site of the SamTrans Transit Village, a Transit-Oriented Development that threatens to intrude upon the right of way and constrain the configuration options for high speed rail. Transit agencies at their best!

UPDATE: Menlo Park has posted their draft scoping comments for consideration at the city council meeting on Tuesday 2/24.

If the rain is keeping you indoors, why not curl up by the fireplace with some light reading:

The city of Mountain View posted their draft scoping comments on the peninsula high speed rail EIR/EIS, to be reviewed / approved at the next city council meeting on Tuesday.

The Mountain View packet also includes a draft of the "We The Mayors" letter presenting peninsula communities under a united front. As further described in a Daily News article on Saturday, an alliance of peninsula communities is being formed outside of the Peninsula Corridor Joint Powers Board (Caltrain), which has heavy representation from the cities of San Francisco and San Jose, cities whose interests will not necessarily align with those of the peninsula communities in between.

The town of Atherton also posted their draft scoping comments (see Item 19, pp. 13-42) on the peninsula EIR/EIS for consideration at their 18 February council meeting. Atherton had originally submitted comments on the Bay Area regional EIR/EIS, to which the CHSRA responded (refer to Chapter 22, page 101, comment letter L025). Atherton's scoping letter includes point by point rebuttals to the CHSRA's comments and a forceful argument for tunneling.

Atherton is of course one of the plaintiffs in the lawsuit to overturn the regional EIR/EIS's CEQA certification, which could re-open last summer's decision to route HSR through Pacheco Pass (and Atherton) instead of Altamont Pass. The court documents pertaining to this lawsuit are available on the Sacramento County Superior Court's document server; search under case number 34-2008-80000022.

Finally, Palo Alto has established on their city website a new section on high speed rail. There's not much there yet, but a good place to keep an eye on.

Focus on: San Carlos

San Carlos is about midway between San Francisco and San Jose. It is home to Caltrain headquarters, located just a block from the historic train depot. The depot was built in 1888 by Nathaniel Brittan, from the same stone and by the same masons as Stanford University. If the roof were made of tile rather than slate, you might think you were on The Farm.

Grade Separations

San Carlos is among the few peninsula communities where Caltrain is already fully grade-separated. The grade separations were built south to north, starting with Howard and Brittan Avenues (built 1993-95), followed by a bike / pedestrian tunnel at Arroyo Ave, a large concourse under the tracks at the San Carlos depot near San Carlos Ave, and ending with Holly St (built 1996-2000, in combination with Harbor and Ralston in Belmont). The two grade-separated tracks run on a raised berm which was opened to trains in October 1999. The Howard and Brittan overpasses sat unused for several years after they were finished, while the other projects to the north suffered delays. Due to poor construction phasing, Caltrain operated on temporary shoo-fly tracks (built on the west side of the right of way, alongside El Camino Real) for six years. Traffic and businesses were heavily disrupted by construction.

One might think that after all this pain and anguish, San Carlos would enjoy the prospect of breezing through the improvements required for high speed rail. Think again!

In another example of sheer incompetence, the 1990s Caltrain engineering department conceived all the San Carlos grade separations entirely without accommodation for future additional tracks, even as alarmed transit advocates tried to draw attention to this design flaw. Indeed, quite aside from HSR, the midpoint of the SF-SJ line is one of the most desirable spots to add passing tracks to allow Caltrain express trains to overtake local trains. Unfortunately, such forward-thinking transportation concepts as skip-stop express service were not yet ingrained in Caltrain's culture; the Baby Bullet had not been invented.

Throughout San Carlos, every rail overpass, including the pedestrian concourse at the station, was built for exactly two tracks. Every concrete structure that Caltrain built in San Carlos over the last 15 years will have to be reconfigured or rebuilt to make room for the two additional tracks required for high speed rail. Those concrete structures now constrain the possible placement of high speed tracks and may prevent shifting their alignment to the most optimal position. (Not that Caltrain has ever been known for shifting tracks to their optimal position: the signal in this tongue-in-cheek photo is just north of the San Carlos station.)

HSR Plans

The California High Speed Rail Authority indicates in its EIR/EIS peninsula maps that the tracks will run at "existing ground" level, with a reference to Volume 2, Appendix E, Figure CC-8, which shows four tracks running at grade. This configuration is not consistent with the existing embankment, which would more likely become a retained embankment with walls on each side.

Station

The San Carlos depot is considered a local landmark, so it will not be demolished. Built of sandstone masonry, it is not easily moved, unlike the even more historic wood frame depot in Menlo Park. The Caltrain grade separation project was built right up against it, in the manner of a thick lava flow frozen just short of the eaves. The photo to the right shows how little clearance remains, looking in the southbound direction. Note the textured concrete, strenuously trying (and failing) not to overpower the Richardson Romanesque style of the depot.

The CHSRA plans a four-track station with two center express tracks. This poses a thorny engineering question: how to squeeze four tracks plus two 15-foot platforms between the depot building (to the west) and Old County Road (to the east), while constraining two of the four tracks to use the existing overpass structure alignments. Something will have to give: the depot, the overpasses, or both. The figure at right illustrates the problem by overlaying an aerial photo of the San Carlos depot with a short section of 4-track right of way (red outline) drawn to scale, using the dimensions provided by the CHSRA.

Given the alternatives, perhaps moving the depot doesn't sound so bad after all.

Station Area Development

The city of San Carlos and Samtrans have plans to develop the land between El Camino Real and the tracks into a transit village. This 8.7 acre strip of land is owned by Samtrans, and was formerly occupied by the shoo-fly tracks during construction of the grade separations. The transit-oriented development was awarded to Legacy Partners after a drawn out "visioning" process that began in 2002. Samtrans will retain ownership of the land, and sign a 99-year lease with Legacy Partners. Construction is planned to begin within the next couple of years, well before HSR comes to town.

A Samtrans official has claimed that the development would leave enough room to add two tracks for high speed rail, although details remain unclear. There is enough uncertainty in how exactly the two tracks will be added, given all the existing constraints, that additional physical constrains from the TOD would be unwelcome.

NOTE: This post will be updated continuously, as warranted by additional information or new events relating to San Carlos. Full disclosure: the author lives in San Carlos