What Level Boarding?

Caltrain disagrees with itself regarding which exact platform height to adopt for level boarding. Is it 50 inches or is it 25 inches? You be the judge. Consider the evidence:

Exhibit A: the Electric Multiple Unit conformed contract documents specify that the new level boarding platform height will be 50 inches:

Section 2.2.1.1 Future Level Boarding 

CHSRA trains will run over the same alignment and stop at some of the same stations as JPB trains. The bi-level EMU must therefore have the same interface with the infrastructure as the future High Speed Rail cars, including clearance envelope, and platform boarding height. 

JPB plans to raise platform heights to approximately 50.5-50.75” ATOR (to interface with a vehicle threshold height of 51” ATOR), initially at San Francisco, Millbrae, and San Jose stations. Other station platforms on the JPB system may ultimately be raised to the same level. These requirements will likely require two sets of doors – one at high level and one at a lower level. 

(...) 

To facilitate the scenario where all platforms are raised to the ~50.5” ATOR level, it must be possible for JPB to easily de-activate the lower level doors and add additional passenger seating in the lower level vestibule area. 

Section 3.3.3 Threshold Height / Platform Interface 

EMUs shall be compatible with JPB’s existing platform height (8 inches ATOR) and existing mini-highs (22 inches ATOR). In addition, EMUs must be compatible with JPB’s future level boarding platform height of approximately 50.5 to 50.75 inches  ATOR.   Each car shall be capable of serving both platform heights during the transition from the existing platform height to the future platform height.

Exhibit B: slides from a November 22, 2016 study session of the Mountain View Transit Center master plan, held to solicit input from the city council. In this document, we find out on page 14 that Caltrain plans to adopt a new level boarding platform height of 25 inches:

Design platforms for future level boarding operations, which will begin after the Caltrain fleet is converted from diesel to electric trains. Level boarding at a 25” height (versus the current 8” height) will shorten boarding time for all passengers and meet Americans with Disabilities Act requirements. 

Exhibit C: slides from an October 18, 2016 meeting of the Citizen Working Group advising San Francisco's RAB (Railyard Alternatives and I-280 Boulevard) feasibility study. On slide 11, we learn that Caltrain plans to adopt not one, but two level boarding platform heights. Platforms at 4th/King will be rebuilt to 25 inches, while platforms at Transbay will be built to 50 inches:

For 4th/King it is likely that Caltrain and HSR will operate at different platform heights 

• HSR will operate at 50-inches, Caltrain at 8-inches top of Rail (TOR). Therefore, there will be dedicated platforms for Caltrain and HSR at 4th/King 

Caltrain may change height of their platforms at some time to 25-inches from TOR but still will be different than HSR 

All platforms at TTC to be constructed at 50-inches. Caltrain will use 2nd set of doors at TTC and utilize any platform/track at TTC

This sort of inconsistency would be amusing if level boarding wasn't the most important modernization step that Caltrain must take after the electrification program is completed... and if the EMUs that Caltrain just ordered from Stadler could actually serve a 25" high platform.

The Stadler EMUs won't work with 25 inch platforms

Barring a contract change order and significant technical modifications, the EMUs as specified by Caltrain and as recently ordered from Stadler will not be capable of boarding or alighting passengers at a 25 inch platform.

First, there's the little issue that the floor height of the lower level of the new EMU was not specified in Caltrain's contractual documents. Stadler went with the standard 22" (550 mm) above the rail, according to their specs. Stepping down from a 25" platform into a 22" rail vehicle is frowned upon by regulators. But leave that aside and imagine the trains actually had a 25" floor level that matched a 25" platform.

Unless every single Caltrain platform were to be raised overnight from 8" to 25", a logistical feat that is exceedingly unlikely to be within Caltrain's financial means or capital project planning ability, the conversion to 25" level boarding will necessarily entail a transition period during which EMUs will serve an evolving mix of 8" and 25" platforms. This has technical implications described in the EMU contract documents:

For compatibility with the existing platform height, vehicles will require an intermediate step between the platform height and the lower level boarding threshold height, at approximately 16 inches ATOR.  This intermediate step must be either removable or retractable to support conversion to a high-door-only modification once all JPB platforms have been raised to 50.5 to 50.75”. The vertical face of this intermediate step will be located at approximately 61 inches from car centerline. In addition, a ramp or bridge plate must be provided to interface with JPB’s current mini-high platforms to load wheelchair passengers.  The ramp or bridge plate must comply with 49 CFR 38.95. The entire platform interface system must also be usable during the transition from the current platform height to the level boarding platform height. 

This "intermediate step" is identical to the step arrangement currently found on Caltrain's Bombardier bilevel cars. As long as the intermediate step is present (at 16 inches above top of rail and 61 inches from car center line), here's what the situation looks like at a "level boarding" 25 inch platform, during the transition period:

This is a fatal flaw. A level boarding solution must be structurally and operationally feasible, which this 9" deep by 16" wide gap is not.  This is not a simple matter of welding some plates over the step wells, since the intermediate step would remain in use throughout the transition period, likely several years.

The end goal must be unassisted level boarding at every station, fully compliant with the ADA gap specification of 49 CFR 38.93(d)(1).  Manually operated bridge plates are not okay; conductor-assisted level boarding won't cut it for a punctual and reliable blended system where HSR and Caltrain must share primarily two tracks.  This means Caltrain should either drop any talk of 25" platforms, or modify the EMU contract post haste with the same retractable bridge plates at the low doors as will be fitted to the 50" high doors.

Level boarding requires a carefully engineered solution and a crisp strategic plan for how to get there. The documents cited above suggest that Caltrain still needs to get it together.

The Blue Doors Will Open

Blue doors open at old 8" platforms (shown here)
Yellow doors open at HSR height

There are noises that Caltrain's new EMU fleet might sport a double set of doors, to enable boarding at two different platform heights.  While this isn't necessarily ideal, it is a reasonable solution given the constraints of the problem.  And yet, the prospect of trains with double the usual number of doors elicits gasps of horror from some transit advocates and industry insiders.  Let's go through some frequently asked questions to explore the roots of this choice, and feel free to ask more in the comment section.

Q. Do you intend for every Caltrain platform to be rebuilt?

A. Yes!  Today, the number of Caltrain platforms that support level boarding is zero.  In order to achieve the short and predictable station dwell times necessary to operate the blended system with acceptable reliability, level boarding is an operational imperative for Caltrain. The most important thing to realize is that Caltrain will eventually have to rebuild every single platform system-wide -- if not to the same height as HSR, then to some other significantly greater height for level boarding than the current 8-inch standard.  Level boarding is not just an option; it is a necessary expense without which blending Caltrain and HSR will fail.  Every platform must be rebuilt no matter what; this is the premise from which the rest of the discussion must start.

Q. But why insist on compatibility with HSR platforms?  Caltrain and HSR are separate systems serving separate markets, so why is this compatibility thing such a big deal?

A. Compatibility with high-speed rail is important for two major reasons.

First and most importantly, the San Francisco Transbay Transit Center will be a system-wide bottleneck for both Caltrain and HSR, with just six platform tracks.  This cramped but critically important terminus will be even more constrained if the two operators are forced to use segregated platforms.  In a segregated world, opposing flows of arriving Caltrain and departing HSR could conflict in the station approach tracks, triggering cascading delays should even one train fall behind schedule.  With platform compatibility, any arriving train can be routed to any available platform, minimizing the domino-effect of delays.  The Transbay designers know this issue is the Achilles' heel of the entire design, which is why they are pushing Caltrain and HSR towards compatibility.  The risk of an occasional equipment failure or medical emergency causing a system-wide meltdown depends on the probability of such an incident, combined with the underlying resiliency and flexibility of the infrastructure.  A segregated Transbay design is asking for trouble when things don't quite go according to plan.

Secondly, compatibility has enormous cost advantages for sharing station infrastructure, as will be seen below.  The savings from sharing station infrastructure at just four locations along the peninsula (Transbay, Millbrae, Redwood City and San Jose) could easily exceed the combined cost of converting Caltrain to high platforms system-wide.

Compatible platforms if operated carefully will not interfere with HSR security or fare collection methods.  They are solely a means to maximize the utility and robustness of the Transbay Transit Center and to reduce the capital costs of building California's HSR system by about a billion dollars (yes, with a 'B').

Q. Why can't HSR just select a train design with low floors?

A. It's not that easy.  The CHSRA has expressed an understandable preference for service-proven designs, to draw from the widest range of suppliers worldwide.  Very-high-speed trains (VHST) capable of speeds greater than 200 mph typically do not have low floors.  Nearly all high-speed train designs from Europe, Japan and China for the past several decades have featured high floors, with  few exceptions.  To achieve level boarding as mandated by the ADA while still drawing from the greatest possible selection of vendors, high platforms are almost a necessity for California's HSR system.  The only 200+ mph train with a "low" 30-inch floor is the Talgo AVRIL prototype, still in development.  It does not have distributed traction, which will be important in California's mountainous terrain.

The three foregoing questions allow Caltrain's entire range of possible solutions to be encapsulated in one simple flow chart:

Notice that ALL the level boarding solutions require dual level boarding, at the 8" legacy platform height and at whatever new level boarding height is selected.  Dual level boarding is not an easy problem to solve and usually involves some degree of awkward and clunky mechanisms, be they deploying steps, wheelchair lifts, automatic trap doors, or double sets of doors.  Even the supposedly "simple" level boarding scenario at 25" suffers from this complexity, a fact that is either glossed over or completely misunderstood by most advocates of this solution.

Q. So who cares if Transbay is so constrained?  Can't Caltrain just terminate whatever overflow traffic doesn't fit at the 4th and King terminal?

A. Emphatically, No!  Transbay is a key destination that every Caltrain must serve, especially at rush hour.  75% of Caltrain riders are commuting to work, and there are more jobs located within a 1/2 mile radius of the Transbay Transit Center than within a 1/2 mile radius of all other Caltrain stops from 4th and King to Gilroy, combined!  This enormous concentration of jobs in the heart of San Francisco will only increase with the many new office towers going up today.  Terminating even one Caltrain short of this gold mine of ridership would be quite simply counter-productive, a waste of taxpayer money and a failure to meet obvious demand.

Q. Do you understand the enormous effort and cost to do this?

A. It is a large expense, but also a necessary expense.  The cost of raising platforms is not strongly sensitive to height: rebuilding to ~48" is only slightly more expensive than rebuilding to 25", 30", or any other level boarding height.  Rebuilding to the same boarding height as HSR creates an opportunity to have the high-speed rail project defray some of Caltrain's expense for the conversion to level boarding.

The cost of totally rebuilding every platform is generously $10 million per platform, placing Caltrain's system-wide level boarding tab at (very roughly) $10 million/platform x 2 platforms/station x 32 stations = $640 million, less than half of the cost of the modernization project. On the basis of cost per minute of trip time saved, level boarding beats electrification.

Q. Doesn't this whole issue just boil down to a San Francisco Transbay problem that should be solved at San Francisco Transbay?

A. No, this is not just a Transbay issue.  Rebuilding to the same interface as HSR also enables savings of more than a billion dollars where station infrastructure can be shared elsewhere:

• The massive dual-level elevated station, the six-mile approach viaducts, and the "iconic bridge" in San Jose would no longer be required, with platforms shared at ground level within the existing footprint of the Diridon station.
• Squeezing a fourth track under the Millbrae station, requiring hundreds of millions of dollars of tunneling expense, would no longer be required.
• A Redwood City HSR station, configured to provide HSR service to the booming northern end of Silicon Valley, to enable Caltrain to make cross-platform transfers from locals to expresses, and to tie in future Dumbarton Corridor service, would have a much reduced footprint and would more easily fit in the available site.

Factoring in these infrastructure savings, the cost of converting Caltrain to ~48" is actually negative.  It would be unwise not to do it.

Q. Won't rebuilding all the platforms take years and be an operational nightmare?

A. It will take years, but it can happen with relatively little disruption.  Over the past 15 years, Caltrain has rebuilt 37 platforms from the ground up.  Caltrain has a demonstrated track record for planning, funding and executing platform reconstruction projects.  You'll be hard pressed to find anyone who remembers this causing major disruptions.  EMUs with dual height boarding would considerably simplify the logistics of rebuilding platforms, since each station could be rebuilt independently as funding becomes available and as the planning process progresses in each community.

Q. Will Caltrain end up with a mix of high- and low-level boarding platforms, perpetuating this strange dual boarding height situation forever?

A.  No.  The lower set of doors has only one temporary purpose: to enable boarding from 8" platforms during the transition.  All platforms would be rebuilt to ~48", and boarding from the lower level would ultimately be discontinued.  Any remaining 8" platforms would become an impediment to the blended system, because they would introduce longer station dwells with a significant probability of unplanned delay when boarding or alighting persons of reduced mobility.  Making a mess of the timetable will no longer be tolerable, so there will be a strong incentive to finish the job even at minor Caltrain stops to ensure the highest level of punctuality and system reliability.  This makes Caltrain very different from MUNI or some East Coast commuter railroads, where a mix of boarding heights has persisted for decades because there is no operational imperative for 100% level boarding.

Q. Until all platforms are raised, wouldn't accessibility and dwell time be worse than they are today?

A. No.  EMUs with dual sets of doors would board from 8" platforms with the same efficiency as Bombardier cars, with just two steps up from the platform into the lower level of the train.  (Note that trap door designs would not fare nearly as well in this respect!)

Q. Won't dual sets of doors cause passenger confusion and long dwells?

A. Boarding the train will be obvious, based on which doors open.  Alighting requires queuing at the correct door, which can be facilitated by color-coding of the doors, LED displays, and audible messages.  "Next stop, Menlo Park.  The blue doors will open.  (...)  Next stop, Palo Alto.  The yellow doors will open."  Blue and yellow are good contrasting colors that can be distinguished by color-blind passengers.  People aren't stupid, and should someone get confused, the different doors would be within a few steps and within sight of each other so any mistakes would not lead to significant delays.

Q. Won't all these extra doors displace seating areas and reduce Caltrain's seating capacity?

After conversion to level boarding,
blue doors are plugged and replaced with seats

A. Not necessarily.  Caltrain has estimated that dual sets of doors would displace between 78 and 188 seats per train, or roughly 15 to 25% of a train's seating capacity.  This is a temporary situation during the transition to level boarding, and can be mitigated by procuring extra-wide trains with 5-abreast seating and longer 8-car trains to preserve overall seating capacity.  The space lost to extra doors can be used by standees, who do not have many good options on today's Caltrain fleet.  When the platforms are all converted to level boarding, the lower doors can be removed and additional seating can be installed, especially if this feature is designed into the new EMUs from the outset.

In the meantime, to minimize the loss of seating capacity, it would make sense for Caltrain to make seating capacity a selection criterion in the vehicle procurement process.

Q. Wouldn't this create an accessibility problem, in terms of ADA compliance?

A. No.  Just like today, lifts or bridge plates would be required to board persons of reduced mobility from an 8" platform.  There would need to be an in-vehicle wheelchair lift to change levels inside the vehicle, to allow wheelchair users to board and alight at stations with different height platforms, or to avail themselves of an accessible bathroom on the lower level.  This is not a new technology; these off-the-shelf mechanisms are no more complicated than the exterior lifts used on Caltrain's gallery cars.  An example of such a lift can be seen in this video.

Q. Will bicyclists have to navigate interior vehicle steps, potentially while the train is moving?

A. Yes.  These steps could be made wider and shallower (greater tread depth) than anything in today's Caltrain fleet.  The three steps from a 25" lower level to a 48" mid-level floor could be fitted with wheel gutters to allow bicycles to easily roll up or down along the stairs.  This would make the steps far easier to navigate than the four steep steps up from an 8" platform into a 45" gallery car, turning the corner around a pole through a crowd of Giants fans--the scenario that Caltrain bicycle riders are forced to contend with today.  And riders commonly lift, turn and sort their bicycles by destination while the train is moving, so a bit of jostling isn't exactly a new thing for the bike crowd.

Q. Wouldn't trap doors resolve this whole situation with dual doors?

A. No.  Trap doors have numerous flaws, including one fatal flaw: they would preclude Caltrain passing high platforms at speed while still maintaining an ADA-compliant 3-inch gap when stopped at a high platform.  Trains sway from side to side when running at speed, and the alignment between the track and the platform edge isn't perfect; that means the space between the train and the platform needs to be wide enough to prevent platform strikes but narrow enough to comply with ADA rules.  There is currently no rail system in the United States that can do both: there is either a speed limit when passing platforms (e.g. BART) or the gap when stopped is greater than 3 inches (e.g. Northeast Corridor).  Satisfying both constraints (< 3" gap and 100+ mph past platforms) requires a small bridge step to extend from the train when stopped.  This sort of gap filler mechanism is unlikely to be compatible with a trap door configuration.  Trap doors have other disadvantages, such as increased dwell times while the trap door mechanism is moving, sensitivity to damage from dirt buildup and foreign objects commonly found on train floors, and too many steps up from a low platform during the transition period.

The Takeaway

• Level boarding is not just an option; it is an operational imperative for the blended system.  The blended system will not work reliably without it.
• The new EMU vehicles must enable Caltrain's transition to level boarding, or the chance to convert to level boarding will be lost for another 30+ years, the life span of the new train fleet.
• It is appropriate for Caltrain to adopt the same platform height and width as HSR, in exchange for the funding to achieve the transition to level boarding.
• Transitioning to level boarding is complicated regardless of the chosen platform height; there is no easy solution.
• Dual doors are the path to level boarding with the fewest flaws, under the imposed constraint of high-platform HSR.

Caltrain Has a Dwell Time Problem

Actually, Caltrain has two dwell time problems. The first is that station dwell times are too long, and the second is that station dwell times are too unpredictable.  Both of these problems will prove fatal to the blending of Caltrain and HSR services on "primarily two tracks."

To help visualize why, let's use position-versus-time string diagrams, often discussed on this blog.  Imagine trains following each other on a single track that runs from San Jose to San Francisco (ignore the other direction for now).  This red line is a local train making a lot of stops.  It leaves San Jose, and a while later arrives in San Francisco.  If you looked really closely you might see the individual station dwells, small horizontal kinks that occur whenever the train is stationary and time passes, but when you squint, it looks pretty much like this:

Every once in a while, this local train comes to a station where Jane, a wheelchair user bound for San Francisco, would like to board.  Because we don't have level boarding, getting Jane on board the train involves manually deploying lifts or ramps to ascend the several steps from the platform into the train.  Conductors must help Jane through the mechanics of the boarding process, which can easily take several minutes but feels like an eternity, even for Jane.  Timetable planners allow for riders like Jane by making sure that no other trains are scheduled right behind each other, to absorb these randomly occurring super long dwells without causing a train traffic jam.  They call it padding.  Here's what padding looks like, in pink:

This being a blended system on "primarily two tracks," we've got express trains and even high-speed trains using the same track as Jane's local.  A faster train looks like this blue line:

The blue line is steeper because the express train can cover the same distance from San Jose to San Francisco in much less time.  Here comes the express behind the local:

The timetable planners don't want the express to be delayed.  That's why they left a big gap between the trains, giving the local a good head start out of San Jose so that the express won't catch up to it before San Francisco.  Alternately, here is the local departing San Jose right behind the express:

Once again, a big gap opens up behind the express because the local is so much slower to arrive in San Francisco.  Now it's rush hour, and this is what "blending" soon looks like (not to scale):

In one hour, six trains can arrive in San Francisco.  Our string diagram is full of gaps, which means we are making very poor use of the capacity of our single track.  How do you fix this?

First, you electrify Caltrain.  While this isn't cheap, one of the main advantages of electrification is that EMUs start and stop much more quickly, so that on average, a local can get to San Francisco several minutes sooner while still making the same station stops.  The local will have a higher average speed than it did before.  Compare:

See how the new EMU local train shows up as a steeper line?  That's because it spends less time moving between stations.  (Note to Atherton: electrification is not just an emissions thing.  Tier IV diesel trains can't pull off this neat trick like an EMU can.)  Now this is what the "blended" rush hour looks like:

If you compare it carefully to what we had before, we can now fit eight trains in the span of one hour, instead of six, because those dreaded gaps are shorter.  By increasing the average speed of the locals, we were able to squeeze in more trains (and more passenger capacity).  Caltrain seems content to declare victory and live like this happily ever after.  This is what they envision as the "blended system".  Whenever Jane decides to ride the train, the pink padding still ensures that following trains aren't delayed too badly.

It's better, but still kind of mediocre.  Especially for Jane.

What if the local train could spend less time standing still at each station?  Dwell time can be reduced by level boarding, a step-free and gap-free configuration where you simply walk on or walk off the train, just like when you ride BART.  For a given number of passengers getting on and off the train, level boarding shaves off about 1/3 of the station dwell time since they can all shuffle on and off more quickly and seamlessly.  The magic of reducing dwell times is that while the train's actual speed is no higher, it still gets to San Francisco sooner, because it saved a few seconds during each station stop.  A few seconds here, a few seconds there, and pretty soon you're talking several minutes.  The average speed went up without the actual speed increasing!  The string for an EMU local with level boarding now looks like this:

If the local arrived in San Francisco ten minutes earlier thanks to electrifying Caltrain, it can arrive another five minutes earlier than that by having level boarding at all stations.  Electrification saves time between station stops, and level boarding saves time during station stops.  The two work together as perfect complements to each other.

The diagram above is actually wrong, and here's the second amazing thing about level boarding: Jane can get on and off the train like everybody else.  Not only does this give Jane the dignity and equal treatment that she deserves, but it saves everybody else the grief of those randomly occurring Jane delays.  Because dwell times are now predictable, timetable planners can get rid of the padding they applied in case Jane wanted to ride before.  Like this:

If you like probability distributions, here is the effect of level boarding on the probability distribution of dwell time:

Caltrain commissioned a study of station dwell times, which found that across a sample of 5149 station dwell observations, the median duration from wheel stop to wheel start was 49 seconds.  The median excludes abnormally long dwells, such as those occurring when Jane wants to ride.  The average dwell time does account for Jane and is 58 seconds, practically an eternity.  That was back in 2010.  Today, with the system bursting at the seams, average dwells are getting so long that the timetable was recently adjusted to make chronically late trains into slower on-time trains.  With level boarding, typical dwell times could easily be cut to 30 seconds.

Level boarding really improves the situation for rush hour:

We're really cooking now.  We can squeeze 12 trains through in one hour on the same track.  That represents a massive capacity increase, with the combined effect of reduced and predictable dwell times providing a similar benefit as electrification alone did.

Caltrain staff just doesn't seem to get this, and they are certainly not helping their board of directors understand the issue. They think of level boarding as primarily an optional comfort feature. Here is their view of level boarding, from a recent board meeting quarterly update:

First of all, they don't even call it level boarding. Dual doors!  What a pain!  Requested by interloping stakeholders, or imposed by those annoying HSR people!  Ew, it's so complicated!  It costs $30 million to equip the new fleet!  It's almost as if they are disowning the very idea of level boarding, and reluctantly trying "not to preclude" some unspecified future decision because this stuff is just too hard to think about.  Presented this way, you couldn't blame the board or the public for thinking this is a stupid idea.  Where's the upside?

The upside is this: dual doors are the only realistic path for Caltrain to achieve level boarding, and level boarding is the only way that the blended system can work on "primarily two tracks."

This issue cannot be taken lightly, because the next opportunity to start a Caltrain conversion to level boarding will not occur until 2050, when the new fleet reaches the end of its useful life.  That's because the new fleet, as about to be ordered, cannot provide level boarding at a platform height of 25 inches.  The entire system would have to be shut down for the trains to be modified and all platforms to be rebuilt at that height.  So, doing nothing today and blindly kicking the can down the road until 2050 is not an option.  A prudent and strategic $0.03 billion down payment for a gradual transition to level boarding is minuscule as a fraction of the $2.2 billion modernization budget, and unlocks great potential for quicker and more punctual commutes as soon as the next decade.

Dual doors are a customization that amounts to less than 5% of the price tag for new trains ($30 million out of $648 million bid price).  They can hardly be used as an excuse for the massive increase in the cost of Caltrain modernization.  They will help to address Caltrain's dwell time problem.

Caltrain has a dwell time problem.  The first step is for everyone (staff, board and public) to understand it.

Going the Extra Inch

Assisted level boarding on
Amtrak's Northeast Corridor

To enable wheelchair users to board a train without assistance, the Americans with Disabilities Act (ADA) requires level boarding platforms to have a maximum 3-inch horizontal gap with the train floor, and a maximum height mismatch of 5/8 inch (see 49 CFR 38.93).  When this specification is met, wheelchair users can safely and quickly board a train by simply rolling across the narrow gap between the platform and the train, giving it no more thought than when using an elevator.

Today, few commuter rail systems in the United States offer this level of accessibility.  The NCTD Sprinter (see video) may be the only one, and is often classified as "light" rail.  U.S. systems with level boarding (such as in the Northeast) have a gap of six inches or more between the platform and the train, requiring the use of bridge plates for a wheelchair user to board.  As shown in the photo above, train crew members must assist with the process of deploying the bridge plate, monitoring the wheelchair, and re-stowing the bridge plate.  Assisted boarding can easily extend station dwell times and cause delays, even on a rail system with level boarding.  These delays are allowed for by padding the time between successive trains, to prevent a delay from cascading to multiple trains.

So, just build the platforms close enough to the tracks and we're done, right?  It's not quite that easy.

Dynamic Vehicle Envelope

Dynamic envelope as defined
for Caltrain electrification

When trains are moving at speed, they can sway from side to side.  Suspension failures or shifting loads could even cause them to sag or lean to one side, requiring additional clearance between the track and nearby obstacles.  Station platforms form one such obstacle.  Caltrain's electrification RFP defines a dynamic vehicle envelope (shown at left, from page 95 of this PDF document) that encompasses the range of motion that can be expected from Caltrain's existing diesel fleet, future high-speed trains, and freight trains that use the peninsula corridor.  The dimensions of the dynamic envelope constrain how far from the track center line any future level boarding platforms would have to be set back, in order to prevent what is known as a "platform strike" from a train passing at speed.

• 8" platforms (existing) are 64" from track center
• 25" platforms would have to be 67" from track center
• 30" platforms would have to be 68" from track center
• 50" platforms would have to be 70" from track center

Meeting the ADA Gap

Unassisted level boarding in Zurich
(Siemens photo)

The vehicle envelope, because it is dynamic, forces a clearance between platforms and trains that is wider than the 3-inch ADA maximum for unassisted boarding.  To provide unassisted boarding without bridge plates, the gap can be bridged automatically by a moving step that extends from the train, a moment before the door opens.  As shown in the photo at right, this step is the key to ADA-compliant unassisted boarding for wheelchair users, and provides a more comfortable boarding interface for bicycles, strollers, luggage, and anything else with wheels.  The step retracts after the doors close, a moment before the train departs.

These gap-filling steps are quite common outside the confines of U.S. commuter rail, and all major vehicle manufacturers worldwide can provide them if the customer asks.  Video examples:

• Vienna, Austria (Stadler)
• Leipzig, Germany (Bombardier)
• Stuttgart, Germany (Alstom / Bombardier)
• San Diego, California (Siemens)

Another common and useful train feature is an automatically leveling suspension, to control the plus or minus 5/8" vertical alignment between the train floor and the platform regardless of passenger load or wheel wear.  A nice bonus of such a system is that it can measure passenger loads in real time.  This too can be provided by vehicle manufacturers if the customer asks.

Caltrain's Approach: What Gap?

Caltrain is now taking a "not to preclude" approach to level boarding, attempting to future-proof the new EMU fleet for any future decision regarding level boarding, pending the outcome of additional planning for the Caltrain / high-speed rail blended system.  This approach is largely a result of not having seriously thought about or planned for level boarding until quite recently.

[Update 6/14/2015: turns out that Caltrain's EMU RFP does require the ADA gap specs for unassisted level boarding!  My source had it wrong.]
As it turns out, Caltrain has no intention to comply with the ADA gap requirement.  Never mind the gap.  As will be apparent in the upcoming vehicle RFP, the new EMU fleet will comply with the ADA using crew-assisted boarding with bridge plates, even after level boarding platforms are built and regardless of the selected platform height.

If Caltrain fails to specify gap-filling steps and leveling suspensions for their new EMU fleet, then wheelchair users will still need crew assistance to board or alight, resulting in random and unpredictable impacts on station dwell times.  Such a failure would preclude reliable and punctual operation of the blended system, increase the amount of timetable padding between trains, and limit the capacity that can be extracted from the peninsula rail corridor before expensive and controversial infrastructure upgrades become unavoidable.  Gap-filling steps and leveling suspensions are perfect examples of small off-the-shelf features that pay off in the long run.

In order "not to preclude" an efficient blended system that extracts the highest capacity from limited infrastructure, Caltrain should require that the new EMU fleet be equipped for ADA-compliant unassisted wheelchair boarding, once new level boarding platforms become available.  Because the new fleet will be in service until the year 2050, this capability cannot be an afterthought and must be engineered into the new trains from the outset.

Compatibility, Done Backwards

Steps from an 8-inch platform
into a Bombardier bilevel car
with a 25-inch floor.  The first
step is 10", the second 7"

Caltrain justifies its desire to procure a new EMU fleet with 25" floor height thus:

With a 25” floor threshold, the new fleet will still be compatible with the existing fleet and platforms and could transition to level boarding over time.

"Existing fleet" in this context means the Bombardier bi-level cars, known to the layperson as the red Baby Bullet cars.  Caltrain plans to keep these cars for a few years after the new EMUs arrive.  The Bombardiers already have a floor height of 25" above the rail, although  existing 8" platforms currently require two steps up, as seen in the photo at right.

The statement above sounds like a genuine interest in compatibility, and at first reading seem to make sense.  But let's analyze Caltrain's ideas about compatibility more closely.

Compatibility with Existing Fleet

Suppose for a moment that we planned to "transition to level boarding over time" at 25 inches, because we think it's smart to match the floor level of the Bombardier cars so that we can keep using them after the conversion to level boarding.  Is that even a feasible scenario?

The "before" and "after" cases are straightforward.  Before transition is just the way things are today.  After transition is complete, the entry steps are easily modified to match the interior floor height, achieving gap-free level boarding just like this photo of Utah FrontRunner Bombardier cars docked at 25-inch platforms.

It's the "during" case where things fall apart: because the step modification involves a one-time visit to the shop, there is no way for a Bombardier train (or any other train in Caltrain's existing fleet!) to serve an evolving mix of high and low platforms in daily service during the "transition to level boarding over time".  There would be a 7-inch deep, foot-wide trough between the platform and the car floor that would qualify as a serious tripping hazard even for an able-bodied passenger.  This configuration would be illegal under a number of federal regulations.  The Bombardier fleet would have reduced utility for the duration of the transition to level boarding, likely to be several years.  So let's say it again:

Bombardier cars cannot serve an evolving mix of 8" and 25" platforms during a transition to level boarding over time.

Once the transition to level boarding is complete, maybe in the mid-2030s, the Bombardier cars will be at the end of their useful life.  Given the limited remaining lifetime of the Bombardier cars, their inflexibility during transition, and their dwindling residual value, there is little value in matching the new level boarding platform height to the Bombardier cars.  There may even be negative value in doing so.

Compatibility with Existing Platforms

Mini-high platform built on top of
8-inch platform.  The top of the
mini-high is at 22 inches ATOR.

This is primarily an issue of wheelchair boarding.  Matching the new EMUs to the 25-inch floor height of Bombardier cars allows Caltrain to procure EMUs without vehicle-borne wheelchair lifts, which are expensive to purchase and maintain.  Instead, the EMUs would re-use the existing mini-high platforms to perform wheelchair boarding, using a bridge plate to span the large gap between the mini-high platform and the train.  (Recall this ~3-foot gap is present in the first place because of a California PUC regulation on side clearances for freight trains).

To ensure that a wheelchair user can safely navigate across the bridge plate, its maximum slope is set by ADA law under 49 CFR 38.95 as follows:

• 1-in-4 for a height change of less than 3 inches from platform to train
• 1-in-6 for a height change between 3 and 6 inches
• 1-in-8 for a height change between 6 and 9 inches
• 1-in-12 (similar to building wheelchair ramps) for a height change greater than 9 inches

Suppose for a moment that we planned to buy EMUs that have to make use of the existing mini-high platforms, which are built 22 inches above the rail and set back 8 feet from the track center line.  What we have is a geometry problem: the ADA slope regulations constrain the vehicle floor height that is reachable from the existing mini-high platforms.  The maximum reachable height is about 27 inches, which (after accounting for a bit of margin) may explain Caltrain's fixation on 25 inches.

But then consider also: each mini-high platform is worth (generously) about $150k to replace.  On a system with 27 stations, 54 mini-high platforms will cost about $8 million to replace.  While that sounds like a lot of money ("Eight Million Dollars!") this sum is a pittance on the scale of the investments being contemplated.  Eight million dollars is two percent of the cost of the new EMU fleet, and less than a percent of the cost of the electrification project.  Put simply, the mini-high platforms have insignificant value and are a trifle to replace.  Designing Caltrain's future around them is certainly penny wise, but quite possibly pound foolish.

Thinking Inside the Box

While Caltrain is no doubt very attached to its growing collection of mini-high platforms and its expanding Bombardier fleet, neither of these items should drive the design of the future platform interface for level boarding.  25 inches is a fine platform height, but selecting it on the basis of these two perceived "constraints" could prove very unwise in the long run.

Caltrain appears to have an uncomfortable relationship with the level boarding issue: it's a distraction from their current big project to electrify the railroad, it's logistically far more challenging to plan for than just stringing up some wire, it involves fighting clearance regulations that are dear to the freight railroads, it isn't funded, and they'd rather not think about it right now because the issue gives them a headache.

But what sort of modernization is this if level boarding becomes a careless afterthought?

Still Dithering on Level Boarding

EMU low door configuration

Recent documents seeking regulatory relief from certain FRA requirements for Caltrain's new EMU fleet reveal details of the interface between the train and a station platform.

The lower doors of the EMUs will feature a deploying step at 15 inches (measured above the top of the rail), halfway between the 8-inch platform and the 22-inch train floor. The resulting step arrangement, when deployed, is similar to the existing Bombardier cars, although the floor height of the Bombardiers is 3 inches higher.

So far, so good.

A closer examination of the step mechanism (see Stadler engineering drawing, as submitted to FRA) shows that the step module retracts upward from its 15 inch deployed height, using a cam mechanism, and stows with the step tread 2.5 inches below the door sill. This makes the step unusable for an ADA-compliant level boarding interface, where it might have been configured to close the gap with a 22" platform, at the same height as the train floor. Recall that ADA regulations for unassisted level boarding require a platform gap less than 3 inches, with vertical discontinuity less than 5/8".

One faction of Caltrain staff evidently envisions level boarding using the low doors of the new EMUs, but the engineering drawing proves this is out of the question without a complete redesign and replacement of the door step mechanism. Even then, there are serious questions about the feasibility of a gradual transition to level boarding where the train fleet must serve a slowly evolving mix of 8-inch and raised level platforms.

As per usual with level boarding, the end goal is clear, but getting there is the hard part and often involves lots of hand waving.

Consultant Still Doesn't Get It

Not only is the lower level door step mechanism unsuited for future level boarding, but Caltrain's vehicle engineering consultant, LTK Engineering Services, states that low platforms will be used indefinitely. On page 1 (PDF page 5) of the recent FRA waiver application, we read:

Initially, Caltrain will utilize only the lower level doors to serve their existing 8-inch platforms. Once CHSRA service begins in the corridor, there will be a station or two that will have high level platforms and will be served by the Caltrain EMUs via the intermediate level doors. Other Caltrain stations will remain low level and will be served by the lower level doors.

No! Continued use of 8-inch platforms means long dwell times and time-consuming conductor-assisted boarding for persons of reduced mobility using a manually emplaced bridge plate. This antiquated state of affairs cannot be allowed to persist. Blithely ignoring the minutes that can be saved while the train is at rest is unacceptable, especially after spending two billion dollars to save minutes while the train is in motion.

It is time to adopt a policy on level boarding, and to push Caltrain's staff and consultants to reach agreement on the technical approach to get there. Here we are in 2018 and there is still obvious disagreement about whether to implement level boarding at all (a no-brainer if you look at the big picture) and at what height, using what doors on the new EMU fleet. Stop dithering and do it!

Footnote: there are multiple waiver petitions relating to EMU design details.
FRA-2009-0124 Tier I Alternative Vehicle Technology crashworthiness (approved)
FRA-2017-0104 Position of bathroom car emergency exit window (approved)
FRA-2018-0003 Use of upper doors in lieu of emergency exit windows (denied)
FRA-2018-0067 Emergency brake handles, grab irons and steps, clearances (pending)

EMU Draft RFP

Caltrain recently published their Electric Multiple Unit (EMU) Request for Proposals (RFP) in draft form, to obtain feedback from potential proposers prior to the formal issue of this document in August 2015.  Here are some initial impressions:

What's Pleasantly Surprising:

• Level boarding is a serious consideration throughout the RFP.  Caltrain appears to recognize the importance of this issue: it's the Next Big Thing after electrification, and cannot wait until the next round of vehicle replacement in the 2050s.  The RFP shows that Caltrain is starting to walk the walk, not just talk the talk.
• Platform sharing and full blending with high-speed rail is firmly on the agenda with "Option B," a dual boarding height train that enables an eventual transition to level boarding at 48 - 51" height.  This solution has been described and advocated on this blog as the best one available given the constraints of the problem.  Most people who reject this solution ultimately take issue with one of the constraints, but once you accept these constraints, "Option B" starts to make more sense.  Proposers are asked in the draft RFP to further evaluate its feasibility and cost impact.
• In section 3.3.3, future capability for level boarding is described as ADA-compliant with a 3-inch maximum horizontal gap and a 5/8-inch maximum height mismatch.  Section 4.2.3 specifies a pneumatic leveling suspension to meet the vertical tolerance. It looks like Caltrain  is going the extra inch after all, which is commendable.
• The vehicle static envelope in Appendix C is a full 3.4 meters wide, enabling the use of extra-wide trains, wider than the conventional AAR plates.  While Caltrain doesn't seem keen on 3+2 seating (something about the "middle seat" situation), extra width that takes full advantage of the static envelope is good for all uses besides seating.  Let's hope the proposers aren't timid about this.
• While it isn't immediately obvious from looking at the raw numbers, the run times required in section 2.3.6.2 are fairly aggressive and will require some sporty power-to-weight ratios.  This high level of acceleration and braking performance is good for the blended system and will ensure that the most can be made of shared tracks.
• In section 6.4.10.4, door controls are required to be installed in the driving cab, offering the possibility of consolidating and automating a task currently performed by conductors.
• In section 14.4, an automatic station announcement system is specified to automate a task currently performed by conductors.  This isn't exactly surprising for a modern train, but Caltrain and its labor practices sometimes seem stuck back in the 20th century.
• In section 14.9, the trains are required to be pre-wired (if not yet equipped) for passenger Wi-Fi.  For a rail system that serves Silicon Valley, that's overdue by easily a decade.
• No trap doors!  That always seemed like a horrible way to achieve level boarding.

What's Disappointing:

• The RFP is highly prescriptive.  The cost of preparing such a voluminous requirements specification, and then to formally verify such a large number of requirements, will easily run into the millions of dollars.  So much for off-the-shelf procurement.
• In section 2, no allowance is made for articulated trains (e.g. Bombardier Omneo) or for trains with mixed bi-level and single level arrangements (e.g. Siemens Desiro HC).  The desired EMU is prescribed as a set of traditional bilevel cars each about 85 feet long.  A better approach would be to define a minimum passenger capacity per unit length, leaving more room for creative and unconventional interior layouts.
• Still no detailed thought appears to have gone into how to transition to level boarding under "Option A".  The height of 24 or 25 inches is intended to match Caltrain's existing Bombardier bilevel cars, which is a bit mystifying since there is no feasible transition to level boarding using these cars.  Section 3.3.3 basically asks for proposers to figure it out for Caltrain: "Heights below 24 inches will be considered for future level boarding if the Contractor can demonstrate conclusively that the height is advantageous for JPB’s envisioned service and compatible during the transition to that envisioned service."
• Section 12 requires all doors of the train to open at every stop, as they do today.  To reduce wear and tear on the door mechanisms, modern vehicles often come equipped with interior and exterior push buttons for passengers to initiate door opening.  Instead of opening the doors by default, the crew-operated door control station should de-inhibit the doors to be opened only as requested by passengers at each individual door.
• Section 2 envisions that trains would be lengthened from 6 cars (~150 m) to 8 cars (~200 m) at some future date.  This is far too timid a capacity expansion.  A more flexible and future-proof approach would be to order more 150 m trains and double them up-- after the necessary platform extensions are constructed at stations with the highest ridership.

What's Weird:

• Section 2 requires shorter 6-car trains to have their performance de-rated (by software) to the same performance as a longer 8-car train.
• Section 23.2.2 requires the delivery of 200 (two hundred!) 1/50th scale models of each car type for "internal and external distribution"... That's some serious schwag!

What's Missing:

• "Option B" with dual boarding levels requires level boarding at 48 to 51 inches ATOR but fails to describe the basic platform interface dimensions, including height above rail, offset from track center, and tolerances thereon.  Proposers are unlikely to be able to design against such a critical interface when it hasn't even been defined.  This data should be agreed upon with the California HSR Authority, after some technical decision making that may have to occur sooner than they would like.
• In section 3.3.3, Caltrain requires that "the entire platform interface system must also be usable during the transition from the current platform height to the level boarding platform height," a stealth requirement that makes "Option A" trains at least as mechanically complex as the "Option B" trains, by requiring boarding capability at two different heights (8-inch legacy and 25 inches with ADA-compliant level boarding).  A requirement of such great importance and design impact ought to be made more explicit, saying what it actually means and using the word "shall".
• The door control system (section 12) envisions 100% manual operation of the doors by train crews.  This may not properly address the challenge of operating during a platform height transition, when each individual platform may need to be raised in successive construction phases to avoid closing the station or doubling the construction footprint for temporary platforms.  With manual door operation, the risk of human error resulting in opening a door at the wrong platform height will likely be unacceptable, particularly to regulators such as the CPUC.  It may be warranted, at the cost of some additional complexity, to require a platform sensing system that automatically inhibits door opening when the incorrect height is sensed, preventing crew errors and potential passenger injury.

Please use the comment section to add your own review of this document.

Level Boarding: Still Not Getting It

The good news: Caltrain has initiated a small study effort to develop a level boarding roadmap, as part of its portfolio of capital projects.

The bad news: in the summary of this study, Caltrain shows no sign of grasping the purpose of level boarding. We might need to display it on a freeway billboard, like this:

Caltrain does a very nice job of explaining the benefits of electrification. Faster acceleration leads to shorter trip times, a strong message that they hammer often. On level boarding, however, the messaging is muddled. It's something-something about steps? Easier and more inclusive access?

NO!!!

It's about shorter trip times, just like electrification. While electrification saves time in motion, level boarding saves time at rest. The savings are big: cutting station dwell time from 45 seconds (typical for Caltrain today) to 30 seconds (typical for BART, which has level boarding) is worth almost as much "acceleration" as electrification. Electrifying without level boarding is half-baked, and Caltrain should be spending a lot more on level boarding than distractions like BEMUs. Please return to your core mission to quickly and efficiently get people where they are going.

About these numbers: the diesel trip time is for an all-stops local with 45 second station dwells and 15% padding. The EMU trip time has the same dwell and padding assumptions. The level boarding time assumes that station dwells drop to 30 seconds, and padding is cut down to 10%. The lower padding is appropriate because level boarding not only makes dwells shorter, but it makes dwells much more consistent and predictable, as discussed previously. If two wheelchair users need to board, it takes the same 30 seconds, not five minutes of staff assistance. Here are the detailed stop-by-stop stats and string diagrams if you want to tinker with assumptions.

Level Boarding is Legal in California

Arrow level boarding platforms
at San Bernardino, CA

Comments to old posts on this blog are stored in a moderation queue that your author doesn't visit often enough. Over a year ago, commenter jpk122s discovered quite a gem: an official resolution by the CPUC (California Public Utility Commission) that level boarding station platforms are not bound by General Order No. 26-D section 3.4. This means it's nerd time.

Some California Background

The CPUC regulates all railroads in California, including their clearance dimensions under General Order 26-D. This regulation, originally published in 1948, requires all mainline train platforms to be no higher than 8 inches above top of rail per section 3.3. If you want to build a station platform higher than 8 inches, it needs to be set back at least 7'6" from the track center line per section 3.4. This requirement is deeply inscribed into the built environment of train stations around California, including Caltrain's.

• The taller platforms used for boarding passengers with reduced mobility, known as "mini-highs" and cluttering the north end of most Caltrain station platforms with ramps and railings (see diagram below), must be set back at least 7'6" per section 3.4. This is quite far from the track, requiring the use of bridge plates to cross the wide (~3 foot) gap between the mini-high and the train.
  
• The 48" level boarding platforms used by SMART (in Sonoma and Marin counties) are closer than section 3.4 requires, but as mitigation, a set of gauntlet tracks allows freight trains to stay clear.
• The 23.5" (ish) level boarding platforms used by Sprinter (Oceanside to Escondido) are closer than section 3.4 requires, but as mitigation, they have folding edges that tilt up and out of the way of freight trains that pass during the night.

Current Caltrain platform standards

These examples are all Rube Goldberg solutions that are expensive, clunky and inconvenient – especially when considering that nothing physically precludes freight trains operating past high platforms, as is common practice on the east coast.

Then, along came the San Bernardino County Transportation Authority, with a request for an exemption from section 3.4.

Level Boading for Arrow

Arrow is the brand name for a new passenger rail service linking San Bernardino to Redlands. This service uses Stadler FLIRT diesel multiple units, of a standard vehicle design sold in more than 2500 copies around the world. The platforms are built for level boarding at 23.5" to comply with the accessibility requirements of the Americans with Disabilities Act (ADA). Rather than contrive a new technical solution to comply with GO 26-D section 3.4, the parent agency did something unusual: they asked for an exemption.

The May 5th, 2022 resolution adopted by the CPUC, an agency known for its conservatism and dogged focus on safety, was surprising: "The RSD [Rail Safety Division] has determined that an exemption from General Order 26-D, Section 3.4 is not necessary since it is preempted by the federal Americans with Disabilities Act (ADA)." Section 3.4 (a state regulation enacted in 1948) is preempted by the ADA (a federal law enacted in 1990). The resolution continues:

General Order 26-D, Section 3.4, sets forth a minimum clearance requirement for station platforms. However, this provision of General Order 26-D is preempted by the ADA, which requires a different platform height and distance from track center line to accommodate the introduction of the Multi Unit (MU) equipment– and thus, results in a smaller clearance area – than what is set forth in General Order 26-D, Section 3.4.

Interestingly, the freight railroads that usually complain about the slightest infringements to their operating environment did not comment on the resolution before it was adopted by the CPUC.

Implications for Caltrain Level Boarding

Perhaps Caltrain already knew this all along, but this CPUC order implicitly relieves one of the key regulatory constraints to platform heights and level boarding, discussed numerous times in the past 15 years of this blog. It turns out that no waiver of GO 26-D section 3.4 is ever needed.

It may take a year or two before Caltrain finds out the hard way why they need level boarding, but this is a positive development. For that, we have the San Bernardino County Transportation Authority to thank.

Over-Promising on Electrification

Numerous recent Caltrain materials include the following quantitative claims (see slide at right) about the service benefits of the electrification project:

1. A baby bullet train making 5-6 stops will make the SF - SJ trip in 45 minutes, down from 60 minutes today.
    
2. A train making the SF - SJ trip in 60 minutes will be able to stop 13 times, up from 6 stops today.

Both of these claims are greatly inflated. They are easy to verify using a computer program known as a train performance calculator, which numerically integrates the differential equations of motion of a train based on the known characteristics of the track (vertical profile, curve, speed limits, station stops, etc.) and of the train (power, weight, tractive effort, drag, etc.) Physics and math can predict timetable performance quite accurately.

Myth #1: the 45-minute Baby Bullet express

Today's diesel performance
(pure run time, no padding)

Here is what a typical baby bullet run looks like today, with an MP-36 diesel locomotive, six Bombardier coaches, and a load of 600 passengers. There are five stops in this example, each lasting (very optimistically, as riders will attest) just 60 seconds. The pure run time from San Jose to San Francisco 4th and King is 52:22 under ideal conditions, without any margin or padding that is added to a real timetable; compare to the weekday northbound timetable at 64 to 67 minutes, or up to 25% longer (!) than the pure run time. Note that the weekday timetable has been extensively padded lately due to crowding; in 2012, the same run was timetabled at 59 minutes with 12% padding.

Tomorrow's EMU performance
(pure run time, no padding)

All other things being equal, let's substitute an EMU train for our slow diesel. The same run drops to 48:15, just four minutes quicker. This isn't surprising: baby bullet trains spend most of their time cruising near the speed limit, where the faster acceleration of EMUs doesn't provide a benefit. With all other things being equal (including crowding and long dwell times--why would electrification resolve these?) we can expect the timetable for our five-stop baby bullet to drop by the same four minutes, or 60 to 63 minutes. That is a full 15 to 18 minutes slower than claimed by Caltrain! Even if you remove the copious 5-8 minutes of extra padding present in today's timetable and compare to the 2012 timetable, we're still 10 minutes slower than claimed, at 55 minutes.

EMU performance at 110 mph
(pure run time, no padding)

How could you possibly get to 45 minutes? One approach is to raise the speed limit to 110 mph, which is planned in the long term but clearly outside of the scope of the electrification project. Changing only that variable, and slowing down as needed where curves limit the speed to below 110 mph, our EMU now makes the same San Jose to San Francisco run in 41:32, almost seven minutes faster. However, we're still 7 to 10 minutes slower than Caltrain's 45-minute claim, or 2 minutes slower when using 12% padding. Again, the reasons for having such enormous amounts of timetable padding will not suddenly disappear after electrification!

The best way to get there is with level boarding, which alleviates Caltrain's crippling dwell time problem. Level boarding has two benefits: the primary benefit is in the form of reduced dwell time during each stop, and the secondary benefit is in the smaller amount of timetable padding that is needed, thanks to the improved schedule adherence that is possible when the occasional wheelchair lift deployment no longer threatens to inject random three-minute delays. Padding could conceivably be cut to 7%, and dwell time to 30 seconds. No new simulation runs are required-- our five-stop 79 mph EMU makes it in (48:15 - 2:30)*1.07 = 49 minutes on the timetable; the 110 mph EMU makes it in (41:32 - 2:30)*1.07 = 42 minutes.

Caltrain's claim of a 45-minute baby bullet is readily attainable only after three major improvements are made. These are not included in the scope of the electrification project and are currently unfunded:

1. Conversion of the baby bullet fleet from diesel to EMU
2. Implementation of system-wide level boarding
3. Curve realignment, track upgrades and grade crossing safety upgrades for 110 mph

To promise a 45-minute baby bullet run in the short term is at best misleading and at worst a flat-out lie. Once the electrification project is complete, we can expect approximately zero improvement in baby bullet performance, with timetabled runs in the range of 64 to 67 minutes. If the initial slight increase in capacity of the electrification project relieves crowding (but will it, enough to offset the performance loss from dragging a seventh Bombardier car?) then we could return to the 2012 timetable performance of 59 minutes.

Myth #2: the one-hour, 13-stop limited

Let us assume for the moment that padding returns to the 2012 level of about 12%. Assuming 60-second dwells and a 79 mph speed limit, how many intermediate stops can a limited train make between San Jose and San Francisco before the timetable hits one hour?  Subtracting 12% pad from one hour, we need to make a pure run time of 53:34.

With today's diesel bullet performance, Caltrain's claim of six stops in one hour checks out reasonably closely at 54:57 or just over one hour including padding, i.e. close enough. Let's change the assumptions, one by one:

Simulation Case	Pure Run Time	Timetable
Case A, Diesel, dwell 60, 6 stops, 12% pad	0:54:57	1:01:33
Case B, EMU, dwell 60, 6 stops, 12% pad	0:50:10	0:56:11
Case C, EMU, dwell 60, 7 stops, 12% pad	0:52:04	0:58:19
Case D, EMU, dwell 60, 8 stops, 12% pad	0:53:58	1:00:27
Case E, EMU, dwell 30, 8 stops, 7% pad (level boarding)	0:49:58	0:53:28
Case F, EMU, dwell 30, 9 stops, 7% pad (level boarding)	0:51:22	0:54:58
Case G, EMU, dwell 30, 10 stops, 7% pad (level boarding)	0:52:46	0:56:28
Case H, EMU, dwell 30, 11 stops, 7% pad (level boarding)	0:54:10	0:57:57
Case I, EMU, dwell 30, 12 stops, 7% pad (level boarding)	0:55:34	0:59:27
Case J, EMU, dwell 30, 13 stops, 7% pad (level boarding)	0:56:58	1:00:57
Case K, EMU, dwell 30, 13 stops, 7% pad (level boarding), 110 mph	0:53:08	0:56:51

Simulation Case K
(pure run time, no padding)

Case D shows that the maximum number of stops permissible under post-electrification conditions is at most 8, just two more stops than today, and not 13 as claimed by Caltrain. Only after level boarding does the number of stops increase to 13 as shown by Case J, but once again, level boarding is not included in the scope of the basic electrification project. Case K illustrates the diminishing returns from increasing the speed limit to 110 mph; the more stops a train makes, the less benefit there is from the higher allowable speed. Case K (see diagram at right) shows the train almost constantly accelerating and braking, which is not how one would choose to operate given the cost of electricity in the real world.

The takeaway message to Caltrain is this: don't over-promise and under-deliver on the modernization project. Your electrification project reduces time in motion and establishes a foundation for further improvements, but is not sufficient by itself. To deliver the service benefits promised in your public presentations, you absolutely need level boarding to reduce time at rest.

(do I sound like a broken record?)