08 December 2018

Grade Crossing Trouble Ahead

Grade crossing in Denver (photo: RTD)
Denver's RTD has been operating a new 25 kV electrified commuter railroad since 2016. There's a big problem with it: the grade crossings gates are down for too long, which the FRA and Colorado PUC consider hazardous because impatient motorists frustrated by a longer-than-expected wait may drive around the gates just as the train finally shows up. The problem has festered, with  millions spent on human flaggers to supervise traffic at each grade crossing, contractual acrimony leading to lawsuits, and in recent days a threat by the FRA to shut down the entire railroad until the issue is resolved.

What does any of this have to do with Caltrain? The peninsula corridor electrification project uses the same electrification technology installed by the same contractor (Balfour Beatty), uses the same positive train control technology installed by the same contractor (Wabtec), must contend with more than three times as many grade crossings, and therefore, faces the same looming grade crossing problem. For months, the issue has topped the list of risks that threaten the project, and the search for a viable solution is causing the electrification contractor to fall significantly behind schedule.

How grade crossings are supposed to work

The simplest way to activate a grade crossing is for the train to shunt a track circuit at some set distance before the crossing. This is known as a conventional track circuit warning system, and doesn't work well if different trains arrive at different speeds. The point where the crossing activates must be set far enough ahead to give the required warning time before the fastest train arrives at the crossing; this makes the gates stay down too long for slower trains.

The usual solution to this problem is a Constant Warning Time (CWT) system, which uses electrical signals sent through the track to sense the distance and speed of the approaching train. The grade crossing controller can then predict when to activate the crossing such that the warning time is approximately constant regardless of train speed. This is the type of warning system installed today on the many grade crossings of the peninsula rail corridor.

The FRA provides a nice overview discussion of how various types of grade crossings work. The applicable federal regulations are under 49 CFR Part 234.

What happened in Denver

Because the Denver system is electrified, there are large 60 Hz AC traction return currents (at safe low voltage!) commonly present in the rails when a train is nearby. These currents interfere with and prevent the use of a traditional Constant Warning Time system.

The contractor came up with a "smart" solution: the crossings have a traditional track circuit warning system overlaid with a wireless crossing activation system (WCAS) that interfaces with the positive train control system. Software sends wireless messages back and forth between the train computer and the crossing controller. The train and crossing enter into a contract: the train predicts when it will arrive at the crossing and promises not to get there any sooner, and the crossing commits to activate at some fixed time interval before the appointed arrival, staying closed until the train passes. Depending on the circumstance, the train may arrive at the crossing later than anticipated when the contract was entered into, resulting in extended gate down time. When WCAS is inoperative, the old-school track circuit takes over, also resulting in extended gate down time when a train is operating at less than maximum speed.

In early 2016, before the Denver train opened for revenue service, FRA and PUC inspectors found that the crossings activation times were inconsistent, with frequent occurrence of long gate down times and erosion of what is known as "credibility" of the warning system. Things went gradually downhill from there:
  • So as not to delay the much anticipated start of revenue service, the regulatory agencies granted a temporary waiver to allow RTD to begin operating without WCAS, on the condition that human flaggers supervise traffic at each affected crossing, at the expense of the contractor.
  • The contractor tried to tweak the WCAS software to make warning times more consistent. A fudge factor known as the "Approach Condition Adjustment Factor" (ACAF, so known because every fudge factor needs an acronym to sound legitimate) was applied based on the observed statistical distribution of warning times at each crossing.
  • In September 2017, the FRA gave RTD relief in its interpretation of the consistency required for gate downtime, relaxing its unofficial consistency criterion from +/-5 seconds or +/-10% of programmed warning time to +15/-5 seconds for RTD's system.
  • Performance of WCAS failed to satisfy the increasingly picky regulatory agencies. RTD began to penalize the contractor for failing to deliver a working grade crossing solution. FRA inspectors kept writing up excessive downtime violations.
  • The FRA forbade the start of revenue service on a newer rail line that has since been completed. The original plan to create quiet zones, where train horns are not used at grade crossings, was delayed indefinitely to the continuing aggravation of neighboring residents.
  • In September 2018, the contractor decided that the regulatory agencies had invented and enforced new consistency requirements that were not in the official regulations, and sued RTD claiming "force majeure" of a regulatory change. The complaint makes a fascinating read.
  • In October 2018, the FRA provided the latest inspection report (of many) showing continuing non-compliance with the -5/+15 second consistency tolerance.
  • On November 15th, 2018, the FRA fired off a letter indicating that it was fed up with the continuing grade crossing non-compliance, among other things, and threatened to shut down the entire commuter rail system by revoking the 2016 waiver.
  • RTD is lawyering up against the FRA, and submitted a strongly worded legal memorandum with numerous exhibits effectively claiming that the grade crossing problem exists solely in the imagination of the regulators. RTD provided evidence that other railroads (including Caltrain!) commonly experienced long gate down times in violation of the criteria imposed on RTD.
Whatever happens next is sure to be dramatic. The entire saga can be reviewed under docket FRA-2016-0028, which organizes all the documents exchanged between RTD and the FRA relating to the temporary operating waiver.

Some Observations
Measured distribution of 38255 grade
crossing activation times in Denver.
  1. Denver solved the wrong problem. They tried to invent a better mousetrap, something more sophisticated than a constant warning time grade crossing predictor. All they needed to do was to provide the same simple function with a substitute detection method that didn't rely on traditional audio-frequency AC circuits, which are incompatible with electrification. Instead, they decided to invent a better mousetrap involving lots of software, GPS, and wireless messaging, which naturally attracted regulatory scrutiny.
  2. Complexity is bad. Multiplying the number of interfaces and creating dependencies between elements of the system leads to expensive aerospace avionics-like hardware and software that is cumbersome to deploy, test and maintain. System complexity leads to a proliferation of strange and unanticipated corner cases and failure modes.
  3. Software can anticipate when to activate a crossing and prevent a train from showing up too soon, but there is no software in the world that can make a train show up on time.
  4.  Grade crossing activation times naturally follow a statistical distribution that arises from random environmental factors beyond the control of the warning system. The low end of the distribution must never be shorter than the mandated 20 seconds, but the long end of the distribution will inevitably have some outliers. The diagram above shows the measured distribution of 38255 crossing activation times on RTD. Notice the long tail.
  5. Even traditional "constant" warning time systems have this statistical tail. If the FRA inspectors applied the same regulatory zeal to Caltrain as they did to RTD, Caltrain would certainly be found in non-compliance. This isn't idle speculation: RTD gathered the data to prove it.
  6. The criteria for non-compliance, namely a "significant difference" from the prescribed warning time, are subjective. Guidance from the FRA acknowledges as much: "Thus, prudent judgment must be exercised when reviewing the results of warning time testing to determine whether the actual warning time provided during testing was compliant with the standard."
  7. The regulators painted themselves into a corner. They imposed a strict -5/+15 second criterion, which is easy to verify for an inspector with a stop watch and a clip board, but makes the long tail of the activation time distribution an automatic violation that is almost impossible to avoid. In recognition of the environmental factors beyond the control of the warning system, the regulators should have used controlled test conditions or applied a different criterion, such as X% of activations within Y% of programmed warning time. This is harder to verify for an inspector with a clipboard, but the grade crossing controller ought to be able to maintain these statistical records across a very large number of crossing activations.
  8. While electrification is relatively rare in the US, there are numerous railroads abroad that have solved the constant warning time problem in electrified territory. This probably isn't rocket science. The mousetrap already exists.
Lessons for Caltrain
With the grade crossing warning system already at the top of the Caltrain electrification project's risk list and the contractor falling behind, this problem is already getting a lot of attention. The people involved hopefully already realize:

Keep it simple - the job is to come up with a grade crossing predictor that works in the presence of traction return currents. It will be tempting to come up with a more sophisticated custom solution that uses lots of software, but we learned from the CBOSS project, and Denver's travails, that complexity usually leads straight to disaster. The dumber the better.
Document existing conditions - a large database of activation time statistics should be assembled for each crossing as it exists today, to head off a conflict over the subjective nature of the FRA warning time consistency criteria. In the event of a Denver-like disagreement with FRA or CPUC, Caltrain would be in a position to quantify precisely how much more (and hopefully not less) consistent the new warning solution will be, regardless of the selected criterion. Caltrain enjoys the advantage that it isn't building new crossings like Denver, so there is an existing system performance baseline that is already accepted by regulators. That baseline will only be useful if it is thoroughly documented.
Plant the goal posts firmly - Work with FRA towards mutually agreed verification criteria that don't repeat the mistakes made in Denver of specifying a rigid range and then testing in the uncontrolled conditions of revenue service. The activation time distribution will always have a statistical tail. If the consistency criterion can't be met by today's existing grade crossing system, then it's probably a bad criterion.
Make sure we aren't paying for Denver - the contractor needs to be held accountable for the extent to which Caltrain electrification funds (and schedule delays!) are accruing to the Denver project's benefit, if the same grade crossing solution is ultimately pursued in both projects.

21 October 2018

Thinking Big in Redwood City

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

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

Start with a good timetable

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

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

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

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

Deriving the functional requirements for the Redwood City node

To enable this timetable, we need the Redwood City station to have the following attributes:
  1. Four platform tracks serving two 400-meter long island platforms to facilitate both northbound and southbound cross-platform transfers of very long, high-capacity trains.
  2. Platforms centered on the best cross-town corridor, namely Broadway, for convenient access to and from local destinations on foot, by bike or scooter, by bus, or using the planned Broadway Streetcar.
  3. A turnback track that enables certain Dumbarton corridor trains to originate and terminate in Redwood City, without fouling other train traffic, long enough for an EMU-8 train.
  4. A turnback track that enables the San Mateo local to turn back in Redwood City, without fouling other train traffic, long enough for an EMU-8 train.
  5. Elevated grade separation of all downtown Redwood City crossings, enabling free flow of pedestrians, bikes and vehicles under the rail corridor and including the re-connection of streets currently cut off by the existing configuration (e.g. Hopkins and James).
  6. Bus facilities placed directly under the train platforms for seamless connections without the need for an umbrella. Same for an eventual Broadway Streetcar.
  7. No mezzanine level. Mezzanines needlessly drive up the size and cost of stations, and impede and complicate vertical circulation. Street level can fulfill all the functions of a mezzanine, including ticket sales, wayfinding, waiting, retail, and dining.
  8. The shortest and fastest possible vertical circulation (stairs, escalators, ramps, and elevators) using a U-shape viaduct cross section to avoid deep and vertical-space-wasting bridge structure. This helps with transferring quickly between the two island platforms, as would be needed for example to continue from the Dumbarton corridor south to Silicon Valley.
The footprint of such a station is not small. However, Redwood City has plentiful available railroad and transit district land, and the street level interface of such a station can be integrated into the city's street grid, opening up cross-corridor access and avoiding a wall effect. The aging Sequoia Station shopping center, with its wasteful surface parking, can be demolished and redeveloped to make room for an expanded station. Station parking can be moved underneath the approach structures, protected from the elements.

One possible station layout
An optimal station layout has four tracks, with the outer tracks for HSR and express commuter trains. The middle tracks are for commuter trains, and allow both northbound (Dumbarton) trains and southbound (San Mateo local) trains the opportunity to turn at Redwood City without impeding the flow of express traffic. The width of the structure is about 130 feet, as shown in the cross section below:
The northbound express track (Track 3) is tangent. The northbound island platform is 400 x 10 m. The center commuter tracks (Tracks 1 and 2) have curves that are not laid out in detail; this detail does not matter since any train that uses these tracks would slow and stop at Redwood City, using standard trackwork and turnouts. The southbound express track (Track 4) is the tricky one: it wows around the station, passing the southbound island platform on a 7500 m radius curve with approximately 1.5 inches of superelevation (not enough to matter for platform lateral tolerances). This track consists of a double reverse curve with six spiral transitions (tangent, spiral, curve, spiral, tangent, spiral, platform curve, spiral, tangent, spiral, curve, spiral, tangent). The curve is necessary to fit a pair of 400-meter island platforms (long enough to berth a double-length high-speed train) without bulldozing too much real estate.

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

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

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

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

27 September 2018

Growing Caltrain into an 8-Lane Freeway

Caltrain can and should become an eight-lane freeway. Not like an ugly concrete scar tearing loudly through the landscape, but in terms of throughput capacity in people per hour. Today, Caltrain already carries the equivalent of nearly 3 freeway lanes, and more than doubling the system's capacity is hardly a moonshot. For perspective, BART's Transbay Tube carries up to 27000 people per hour, almost double the entire capacity of the Bay Bridge with its ten freeway lanes.

More than doubling Caltrain's capacity has been proposed before and is now being studied by the agency itself, after a decade of not thinking much past electrification.

Capacity calculations can be controversial and rely on many details and assumptions, so the suggested path to expand Caltrain ridership from 3 to 8 lanes of freeway-equivalent is provided in the form of a spreadsheet, embedded below. You can dig into all the numbers and assumptions for each capacity increase and see the underlying formulas for yourself, down to the detailed number of seats in each train car, to understand how it all adds up.

This is a living document, and feedback is appreciated!

08 September 2018

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)

25 August 2018

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 CasePure Run TimeTimetable
Case A, Diesel, dwell 60, 6 stops, 12% pad0:54:571:01:33
Case B, EMU, dwell 60, 6 stops, 12% pad0:50:100:56:11
Case C, EMU, dwell 60, 7 stops, 12% pad0:52:040:58:19
Case D, EMU, dwell 60, 8 stops, 12% pad0:53:581:00:27
Case E, EMU, dwell 30, 8 stops, 7% pad (level boarding)0:49:580:53:28
Case F, EMU, dwell 30, 9 stops, 7% pad (level boarding)0:51:220:54:58
Case G, EMU, dwell 30, 10 stops, 7% pad (level boarding)0:52:460:56:28
Case H, EMU, dwell 30, 11 stops, 7% pad (level boarding)0:54:100:57:57
Case I, EMU, dwell 30, 12 stops, 7% pad (level boarding)0:55:340:59:27
Case J, EMU, dwell 30, 13 stops, 7% pad (level boarding)0:56:581:00:57
Case K, EMU, dwell 30, 13 stops, 7% pad (level boarding), 110 mph0:53:080:56:51

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?)