28 February 2013

The Virtues of Width

The Swiss rail vehicle manufacturer Stadler was recently awarded a contract for 112 bilevel EMU cars to be delivered by 2016 for the Moscow airport express, based on their modular KISS vehicle concept.  A rendering is shown at right, complete with retro-Soviet hood ornament.  (UPDATE 6/2013: datasheet now available).  These EMUs are noteworthy because they take full advantage of the generous Russian loading gauge (the available height and width clearances), resulting in two spacious levels of passenger seating, and also because they use high platforms.  This is a European EMU on steroids, and Caltrain should take notice.

In a blended HSR + Caltrain system, slowly transitioning to full grade separation over a time scale of decades, several constraints exist that will impede Caltrain's ability to add capacity to meet increasing ridership demand:
  • More trains per hour won't work.  Because there are only two shared tracks, the capacity of the corridor (as measured in trains per hour) is limited.  It's going to be a stretch for Caltrain to operate six trains per hour per direction with HSR in the mix, so adding more is clearly out of the question until the much-dreaded additional tracks are built.
  • Longer trains won't work.  Train length is limited at stations such as Burlingame and Menlo Park, where grade crossings are found at both ends of the station platforms.  Until these locations are grade-separated and new longer platforms are built, adding more cars to make longer trains is not feasible.  In any case, most Caltrain platforms limit train lengths to 600 feet (or 7 standard-length cars), at least until they are rebuilt.
  • Taller trains won't work.  Today's bi-level trains already take good advantage of the available height, so there is no seating capacity to be gained by growing trains any taller.
Loading gauge comparison,
Russia / USA / Europe
If more, longer, or taller trains can't satisfy increasing ridership, why not give wider trains a try?  The Russian 1-T loading gauge, shown at right in comparison to the loading gauges of western Europe and Caltrain, allows trains that are almost six inches wider than ours.  Going even a few inches wider than the Russian limit, with a 134-inch wide car shell, would enable five-abreast seating at the same level of comfort offered in Caltrain's existing Bombardier cars.

The Advantages of Extra-Wide EMUs

The diagram below shows a cross section of three double-deck trains: a traditional European EMU of the sort coveted by Caltrain; a Caltrain Baby Bullet car; and a hypothetical extra-wide EMU with comfortable five abreast seating, a few inches wider than the Russian model described above.
Such an extra-wide EMU has several advantages.
  • More passengers per train.  With five abreast seating, 15 to 20% more seating can be provided without increasing train length or train frequency.  Even in those areas without seats, more floor space is available for standees.
  • More usable space.  Extra width makes for more spacious and comfortable vestibules, stairs, and passageways between cars.  High-traffic areas near doors, bicycle racks, restrooms, and luggage racks do not impede the flow of passengers.
  • Lower crew costs.  The number of conductors required on a train is dependent on the number of cars in the train.  Under the present labor agreement, there is a strong incentive to keep train lengths to six cars and to maximize passenger capacity per car.  Five-abreast seating reduces the crew cost (and other operating costs) per available seat.
  • Future-proof HSR compatibility.  Because the CHSRA has already settled on a single-level train architecture for its high-speed trains, it is likely that similar capacity limitations will drive the future California trains to be extra-wide, like the Japanese Shinkansen or the Russian Velaro.  Converting Caltrain to a wider standard helps achieve future platform interface compatibility with HSR, which is not just a matter of height but also of width.
  • Easier conversion to high platforms.  Wider trains can be fitted with both high and low doors to accommodate a platform transition period, without cutting as badly into the seat count as for a normal size train.  (The Russian example is built exclusively for high platforms, but more doors could be added on the lower level.)  What's more, with high platforms built further away from the tracks, those annoying freight trains get a little bit more clearance.
  • Easier vehicle packaging.  From an engineering standpoint, modern EMUs are like a jigsaw puzzle where every vehicle component must find its place under multiple constraints.  More width gives vehicle designers more flexibility to make everything fit, making trains more comfortable and maintainable.
There is very little downside to going wide.  Caltrain's EMUs would be a captive fleet on the peninsula rail corridor, such that expanding a few inches outside the AAR Plate F loading gauge would require only minimal infrastructure modification and would not impede interoperability.  Stadler has once again demonstrated that the car body shells of a modular vehicle can be tailored to any desired size, using different extruded aluminum shapes.

Caltrain should make full use of the generous clearances available on the peninsula corridor.  In a blended future where HSR limits the number of peak-hour commuter trains, extra-wide EMUs with five-abreast seating are an attractive solution for giving Caltrain more rush-hour capacity.

[Update 08/2014: this Swedish academic paper analyzes the numerous advantages of extra-wide trains in far more detail, going into cost elasticities etc.]

17 February 2013

The Blend, HSR Style

The California High-Speed Rail Authority recently published a memo (requested by Kathy Hamilton and CARRD) justifying the oft-questioned claim that the Phase 1 "blended system" presented in the 2012 Business Plan is consistent with the trip-time requirements built into section 2704.09 of Proposition 1A, the HSR bond.  The trip times are in the bond language to prevent funds from being disbursed for projects that are not high-speed rail.

The memo states that the blended system will enable 30 minute non-stop trip times between San Francisco and San Jose.  In support of this claim, the memo provides the speed graph below, to which blue annotations have been added for clarification.  The annotations are necessary because the memo authors evidently did not go out of their way to explain the graph to non-engineers.
San Francisco to San Jose (southbound) speed versus distance graph, annotated.
Notches in the speed profile represent curve speed restrictions.

An independent calculation of the speed profile (using the output of a Train Performance Calculator that numerically integrates the differential equations of motion of the train, taking into account traction, braking, and drag forces) shows that an AGV train limited to 110 mph can travel from San Francisco 4th & King to San Jose in 33 minutes, under a slightly different set of assumptions where the train is slowed by a curve at Palo Alto, uses the existing 45 mph San Jose station approach, and makes an actual stop in San Jose.  After the differing assumptions are reconciled, the math does check out and the calculations are correct.

Those Pesky Assumptions

As for any computer simulation, the results are predicated on a set of input assumptions.  As the saying goes, "garbage in, garbage out"--bad assumptions will lead to bad results.  While the CHSRA's time of 30:22 is reasonable under the particular assumptions they made, the assumptions themselves are questionable.  They include:
  1. The train starts from San Francisco 4th & King, not Transbay.  Starting from Transbay, with its notoriously slow approach, would add about another 3 minutes.
  2. No Caltrain service is allowed for, or in their words, "Caltrain train service will allow for high-speed express train to run unimpeded between SF and SJ".  In Caltrain's blended operations analysis, all HSR services during rush hour make a two-minute stop at Millbrae, which has the effect of reducing the speed differential between HSR and Caltrain.  If HSR were to attempt a 30-minute run during rush hour, it is likely that Caltrain would be impacted by reduced rush hour track capacity, from six Caltrains per hour per direction to four or five.  The stop at Millbrae adds 3.5 minutes to the SF-SJ run.  Such is the nature of compromise.
  3. No padding is included.  In the real world, timetables include a small amount of padding (5 to 7 percent) to allow for the occasional unplanned delay.  Over a half-hour SF - SJ run, a real-world timetable would add at least 1.5 minutes.
  4. The train does not stop in San Jose, so no penalty is taken for the time lost as it slows down.  This alone is worth at least half a minute from 75 mph.
  5. The train uses the least energy-efficient, pedal-to-the-metal driving style.  Brakes are applied fully and at the last moment, and acceleration is at full throttle.  In the real world, where energy and maintenance do cost money, a smoother and more energy-efficient traction and braking profile would add about 1 minute.
  6. No speed restriction is present at Palo Alto, where a double reverse curve limits train speeds to 90 mph.  Slowing from 110 mph would add about 20 seconds.
  7. The train approaches San Jose on an elevated viaduct leading into the proposed upper level at San Jose Diridon, maintaining a speed of 75 mph (as opposed to the slower 45 mph limit practiced on the existing alignment).
  8. Timetables show departure times.  Departure from San Jose would be two minutes after arrival.
In the real world, all those assumptions add up.  In a blended scenario at rush hour, if a passenger picks up the HSR timetable, entries for SF Transbay and San Jose will be no less than 42 minutes apart (30.5 minutes express run time + 3.5 minutes Millbrae stop + 3 minutes Transbay + 1.5 minutes padding + 1 minute energy efficiency + 0.5 minutes slowing for San Jose + 2 minutes dwell at San Jose.)

While a special one-time midnight Cannonball Express run could be achieved in 30 minutes and 22 seconds without violating any speed limits or laws of physics, this figure is not operationally feasible in everyday service and boils down to nothing more than a stunt.  Under the same stunt assumptions, a decrepit old Caltrain diesel could rush from SF to SJ in just 39 minutes.

As the HSR project is litigated, the distinction between a one-time high-speed stunt and a robust every-day train timetable will be important to keep in mind.

10 February 2013

Keep Out the Coast Daylight

The Coast Daylight pulling into
Palo Alto in 1942.  Image from
Caltrans recently published an administrative draft of its California State Rail Plan. This document assembles hundreds of pages of assorted kitchen-sink gobbledygook, fails to mention important topics such as level boarding even once, and reveals a strange fixation with Amtrak's plans to start a new Coast Daylight train linking San Francisco with Los Angeles.

The Coast Daylight, as any old railroader will tell you, was one of the Southern Pacific's most prestigious services back in the golden age of steam trains. The red, black and orange livery of the massive GS-class locomotives (shown in the opening photo pulling into Palo Alto in 1942) is sufficient to throw even the most staid rail buff into convulsions of nostalgia, which seems the likeliest explanation for the sudden urge to resurrect this long-forgotten train.

Why should we care about this anachronism? As it turns out, this latter-day Coast Daylight would terminate at Fourth and King in San Francisco, causing a number of complications and constraints for modernizing the peninsula rail corridor.

Chronic Lateness.  The Coast Daylight's counterpart, the Coast Starlight, has the well-earned nickname "Coast Starlate."  Because the Daylight would also use hundreds of miles of track owned by freight railroads and subject to all sorts of delays, the northbound Daylight would be exceedingly unlikely to arrive reliably on time, causing it to miss its assigned timetable slot on the peninsula rail corridor and delaying everybody else.  With track capacity in the blended Caltrain / HSR system a scarce and valuable commodity, one must ask, should all passengers (especially those who value their time and use high-speed rail) have to pay for Amtrak's inability to keep to a timetable?

Diesels Forever.  The Coast Daylight would be a diesel train, and as the State Rail Plan notes, it could not use San Francisco's new underground Transbay Transit Center station where diesel exhaust is not allowed for.  This would strand it on the surface at the 4th and King station, which is increasingly becoming the object of San Francisco's desire for urban redevelopment.  Plans for Amtrak trains to San Francisco clearly clash with San Francisco's plans for the surface rail yard, a clash that wouldn't arise with 100% below-ground electric trains.

Yet Another Platform Interface.  The Coast Daylight would presumably use the same equipment as other Amtrak long-distance trains, with an entry floor height of 17.5 inches.  No matter what floor height Caltrain ultimately selects for the necessary upgrade to level boarding, Caltrain platforms will end up higher than this.  Because steps down from the platform into a train aren't allowed under ADA and FRA regulations, the result would be separate platform tracks entirely dedicated to the Coast Daylight at San Francisco, Millbrae and Redwood City--or no level boarding for Caltrain.  That hardly seems like optimal use of expensive station facilities.

Negative Return on Investment.  Thanks to speedy and frequent service, the lucrative San Francisco - Los Angeles travel market will go mostly to HSR, with only marginal ridership left to the Coast Daylight to pick up in coastal communities in between.  The Coast Daylight will join many other Amtrak long-distance trains with subsidies per passenger well above the price of a ticket.  The opportunity cost of every dollar spent on reviving the Coast Daylight means that rail service will languish in areas with far greater potential.

Yet Another Tenant Railroad.  Caltrain's plans for modernized train control (known as CBOSS) make a big deal of accommodating so-called "tenant railroads" that travel over Caltrain-owned tracks.  While the Coast Daylight has indeed been accounted for by the Diesel Brain Trust, the very real possibility that CBOSS might fail and get replaced with the HSR train control system could make integration of the blended system unnecessarily difficult.

Blending different services on shared and limited rail corridor infrastructure is a good idea in principle, but blending can go too far.  Amtrak is the spice that will make this blend go sour.  The Coast Daylight should terminate in San Jose or Emeryville, and even nostalgic rail buffs must accept that Amtrak should keep out of the peninsula rail corridor.

02 February 2013

Caltrain Should Use High Platforms

Incompatible platform,
by tracktwentynine
The recent news that CHSRA is considering a joint train procurement with Amtrak could settle an open question about high-speed rail in California, with important ramifications for the peninsula: the selection of a platform interface standard.

A Possible California HSR Platform Standard

Amtrak will procure high-speed trains that conform to its long-established platform interface standard for the Northeast Corridor (NEC), where the platform edges are located 48 inches above the top of the rail and offset laterally by 67 inches from the center line of the track.  While this "high platform" standard dates to the 1930s, it happens to be approximately consistent with the floor heights of the majority of the latest products from big names in high-speed train manufacturing such as Alstom, Bombardier, Hitachi, Hyundai, Kawasaki, Siemens, etc.  For all the mockery that a joint procurement with Amtrak has triggered, it turns out that Amtrak's NEC high-platform standard is, at least dimensionally speaking, quite reasonable for California's high-speed rail system.

If Amtrak and CHSRA do end up pursuing a common fleet procurement, then the California HSR platform standard will be 48 inches above the rail and 67 inches from the track center line.  Even if not, the HSR platform standard is still likely to end up around 48 inches above the rail.

The Need For A Common Platform Standard

So far, Caltrain and CHSRA have demonstrated no sign of coordination--let alone any desire for it--around a common platform interface standard.  All plans so far show stations that are 100% segregated with separate-but-equal tracks and platforms for Caltrain and HSR.  This leads either to elephantine station designs or, when space is at a premium, to severe under-utilization of precious infrastructure and extreme engineering solutions.  In all cases, taxpayers are fleeced and passengers are impeded.

On the other hand, the blended plan envisioned for the peninsula recognizes that shared infrastructure is a worthy goal, to minimize cost and impacts on communities, and to extract the maximum utility from a given investment in new infrastructure.  Taxpayers are spared and passengers better served.

As has often been argued here, Caltrain and HSR should use the same platform interface standard to enable mixed operations even within stations, such as is routinely practiced in European high-speed rail systems.  This would further cut costs and community impacts, increase infrastructure utilization, and maximize operational flexibility--the resilience of the system to disturbances caused by the inevitable failures that happen now and then.  If such an operating concept had a slogan, it would be "any train, any track, any platform".

A Clear and Present Opportunity

Caltrain has an immediate and pressing need to replace its aging fleet, as part of the electrification project.  The majority of the existing fleet dates from 1985 and is nearing the end of its useful life, with breakdowns causing increasingly frequent service disruptions at a time of record demand.  This will only get worse, and Caltrain will have to define a specification for the new trains, including platform interface dimensions, within the next year or two.  While the electrification project will be completed a decade or more before HSR arrives on the peninsula, the new electric trains will be good for at least three decades of service, to about the year 2050.  There is a small window of opportunity to make smart decisions about Caltrain's platform interface in the next year or two that will have far reaching consequences for several decades into the future.  It all comes down to this:

Caltrain should begin a system-wide conversion to high-platform level boarding, starting now.

Objections Abound

Converting to high platforms is a major change.  All major changes bring about the fear of change itself, and unlock myriad reasons why something can't or shouldn't be done.  To play devil's advocate, such objections might include the following:
  • The high-platform standard is wrong for Caltrain; instead, HSR should use low platforms shared with Caltrain.  While this argument has technical merit, it is highly unlikely that a small agency like Caltrain would be able to sway a larger agency like the CHSRA away from the high-floor train architecture that is prevalent in worldwide HSR systems and already built into numerous ADA and FRA regulations and CHSRA documents.  Politics trumps engineering on this one, and it's better for Caltrain to follow HSR to a high-platform standard than to pursue a more technically pure approach (low-platform bi-level EMUs) at the cost of platform incompatibility.
  • Bi-level EMUs are hard to design for high platforms.  This also has technical merit, in that few commuter rail examples exist other than in Sydney and Paris.  None of the common European-style bi-level commuter EMU products on offer from Alstom, Bombardier, Siemens, or Stadler (and often seen in Caltrain electrification brochures) are compatible with high platforms.  A high-platform, bi-level, ADA-accessible EMU could be a challenge to engineer and would break from an "off-the-shelf" procurement philosophy--although some innovative solutions do exist that could meet this constraint.  In the end, if Caltrain asked for a solution, rail vehicle vendors would probably offer it.
  • Caltrain's Bombardier diesel bullet fleet is young, should be kept around, and can't work with high platforms By the time the new EMUs arrive, nine locomotives and 25 Baby Bullet train cars will have reached only about half of their useful life, still quite young in railroad terms.  Caltrain has plans to retain these diesel sets for express service, to reduce the required quantity and cost of the initial EMU fleet procurement.  While this sort of thrift can be expected from an agency that is continually starved of funds, the old trains have an entry floor height of 25 inches and cannot use platforms higher than that.  However, because these trains are of a standard design, they can fetch excellent prices on the second-hand market.  Sell them!
  • A transition to high platforms is nearly impossible to pull off without interrupting service.  This objection assumes not only that the old fleet would be incompatible with the new platforms, but also that the new EMU fleet would be incompatible with the old platforms.  If that were the case, an extended service shutdown could be required to rebuild all the existing platforms to the new standard.  It doesn't need to go this way: the new EMU rolling stock can enable the transition, by providing both high and low doors during the transition period.  After all the platforms are converted, the low doors would be removed and replaced with seating.  Again, if Caltrain asked for a solution, rail vehicle vendors would probably offer it.
  • It is much more difficult to implement level boarding at 48 inches than at 24 inches.  Level boarding is not something that Caltrain can avoid forever.  The operational advantages (brief and predictable station dwell times, not to mention better accessibility for all) are just too great to ignore in a blended scenario.  Inescapably, every last Caltrain platform will have to be rebuilt--including dozens of new platforms built just 8 inches above the rail in recent years.  Regardless of the final platform interface selection, level boarding is going to be a big construction project; whether the platform height is raised by 16 inches or by 40 inches is going to be a rounding error in the final construction budget.
  • Level boarding is a huge change, on the same order as electrification; let's only do one big thing at a time.  No debate there: level boarding is a big investment.  At $5 million per platform and about 70 platforms, the tab comes easily to a third of a billion dollars.  That's not an easy sum to scrape together; however, procuring EMU trains that can serve both high and low platforms during a multi-year transition period could spread or delay this cost.  In the medium to long term, level boarding is not optional.  The cost effectiveness (in minutes of travel time saved per dollar invested) is at least on a par with electrification, and the performance improvement is necessary for blending seamlessly with HSR.
  • Even if Caltrain converts to high platforms, HSR will be kept on separate platforms for security reasons, so why even bother with all this compatible platform trouble?  While all station facilities in the California HSR system are being planned with airport-like security, adopting a common platform standard at least allows a rational discussion of platform sharing as practiced in Europe.  The terror fears are real, but entirely misplaced.  The worldwide history of train terror has demonstrated two basic facts: trains are not as vulnerable as airplanes, and commuter trains are equally vulnerable as high-speed trains (Madrid 2004).  Security theater should not take priority over efficient operations.
  • Caltrain must be compatible with freight, and freight trains can't go past high platforms.  This can be immediately dismissed as an ignorant, California-centric argument. Leaving aside for the moment the many good reasons for banishing freight trains from the peninsula rail corridor, the only obstacle to high platforms--and level boarding of any sort regardless of platform height--is regulatory, not technical.  On the East Coast, freight trains can and do operate on tracks with platforms 48 inches high and 67 inches from the track center line; here is proof on YouTube.
These numerous counter-arguments all have varying degrees of merit, if considered in isolation.  But they cannot be considered in isolation.  Each one of them, if followed to its logical conclusion, leads to a world where Caltrain and HSR must use separate platforms, blending like oil and water.  Now is the time to exercise a little bit of vision to make the idea of a blended system actually work in practice, and shared platforms are a key part of that.

What Caltrain Should Do Now
  • Make it policy to include blended station platforms as part of the blended system
  • Establish an agreement with CHSRA on a common platform interface specification
  • Ask EMU vendors to propose technical solutions for high-platform EMUs and solving the platform transition issue.  This can be in the form of a request for information (RFI), before the electrification EIR or any procurement activity is underway.
  • Stop clinging so desperately to a remnant fleet of diesels after electrification is built.  Saving a few tens of millions of dollars up front is not worth the resulting decades of operational inefficiency.