The primary issue of non-compatible equipment between Caltrain and high-speed trains is that they will not be able to share the same platform edge if level-boarding access is to be provided.Level-boarding access refers to the platform and train floor both being the same height--similar to boarding an elevator--and is mandated by the Americans with Disabilities Act. For an introduction to the subject, covering the various regulatory and engineering constraints, refer to an earlier discussion of platform height. In short, accessible boarding will have to be provided at every train door.
Doty's comment is predicated on two important but unstated assumptions: (1) Caltrain must operate bi-level train cars, and (2) HSR high platforms are not compatible with bi-level train cars. Let's examine those two assumptions.
Must Caltrain operate bi-level train cars?
Since the late 1950s, the peninsula commute has traditionally used railroad cars that have two levels, upstairs and downstairs. Bi-level cars are such a familiar fixture on the peninsula that one might forget to even question how or why they came to be that way. Even future Caltrain vehicles are systematically depicted as bi-levels. The reasons to use bi-level cars include:
- Bi-levels maximize passenger count per train, to provide a given transportation capacity using the fewest trains and crews.
- Bi-levels maximize linear density, or how many passengers can sit within a given train length. This can be useful when platform length can't be extended, such as in Menlo Park or Burlingame, where the platforms are boxed in by grade crossings.
- Bi-levels provide a seat for every passenger, with no standees. The average Caltrain trip length is 23 miles or roughly half an hour, longer than most people would be willing to stand. Because of this, by the way, Caltrain's capacity is defined not in terms of passengers per hour, but seats per hour.
- Bi-levels minimize the mass per seat of the train to reduce energy consumption under intensive start-and-stop usage. (Note, mass per seat can be a misleading metric if a train is designed to provide significant amounts of standing room.)
- Bi-levels take advantage of the generous vertical clearances available on the peninsula corridor.
- Bi-levels have been used on the peninsula as far back as most people can remember.
- Bi-levels differentiate Caltrain's brand image from BART.
- Providing a seat for every passenger results in Caltrain operating at an average capacity of just 39 percent. The numbers don't lie, Caltrain actually hauls around significantly more empty seats than passengers! A few peak-hour express trains do operate near 100% of seating capacity, but conversely, many off-peak trains operate nearly empty. Specifying a new vehicle fleet in terms of peak seating capacity (as opposed to passenger capacity) will perpetuate this extremely low and wasteful average load factor.
- Shorter trip times, thanks to fast-accelerating, short-dwell EMUs, may reduce the need for seating if there's a comfortable place to stand. Most of Caltrain's current fleet doesn't have anywhere to stand at all; if you do, you will quickly be shooed to a seat by a conductor. The need for a seat for every passenger is a self-fulfilling truth: everyone needs a seat because there's nowhere to stand!
- Speeding up service, and especially the turnaround times at each end of the line, allows more trains to be operated using the same number of vehicles and crews. More frequent trains can meet a given level of passenger demand using fewer seats per train.
- 100% grade separation for HSR means that stations will no longer be boxed in by grade crossings and the length of platforms can be increased (within reason, of course.) Extending platforms across grade-separated streets has the additional benefit of providing direct platform access from both sidewalks of those streets, making stations more accessible to pedestrians.
- Caltrain plans to increase peak rush-hour track capacity from today's 5 trains per hour per direction; a conceptual schedule shows as many as 10 trains per hour per direction. Once again, moving more trains per hour can meet a given level of passenger demand with smaller-capacity trains.
One could argue that growing ridership would eventually require bi-level cars anyway--similar to this gargantuan commuter train in New Jersey--an argument that isn't entirely without merit, since rail vehicles typically last for one-third of a century. But this argument would need to be based on a serious, quantitative ridership study.
So, must Caltrain use bi-levels? The answer is not as obvious as one might first expect.
It's even less obvious that Caltrain should provide an actual seat for every customer. Providing convenient and comfortable places to stand, and a more flexible floor plan for standees and bicycles, would increase the average load factor and make more efficient and profitable use of the new vehicle fleet. Rush-hour crush loads could still be met by increasing train length (something that is inherently easy to do with EMUs) and by increasing train frequencies.
Are high platforms compatible with bi-level train cars?
The most important implication of this question is how to pull off the transition from the existing low platforms to the high platforms typically used for high-speed rail, without interrupting Caltrain service during construction. One possible solution to this transition conundrum has already been described.
Assuming such a transition were feasible, would it preclude the use of bi-level train cars?
The quick answer is no. You don't have to go further than Chicago or the Northeast Corridor to see plenty of bi-level trains that board using high platforms--to say nothing about numerous examples abroad. The slightly longer answer is that high platforms don't jive with Caltrain's plans to acquire European bi-level EMUs. The European products that Caltrain is evaluating (bi-level EMUs from Bombardier, Siemens or Alstom... and by now, hopefully also Stadler, which just recently entered this market) all feature doors on the lower level. Low-floor boarding has undeniable advantages:
- It's what the builders already provide off-the-shelf.
- It allows doors to be optimally spaced out along the length of the train, providing good passenger circulation and reducing station dwell times.
- It makes for a much easier transition from today's 8-inch platforms to the ADA-mandated level-boarding without interruption in Caltrain service.
- It allows Caltrain to retain its relatively young Bombardier sub-fleet, if the platform height is established at 25 inches (the floor height of a Bombardier car). One can of course question the wisdom of making a fundamental corridor architecture decision, such as platform height, on the basis of a sub-fleet of 25 standard-issue commuter cars that would fetch excellent prices on the second-hand market.
High-level boarding would definitely introduce a big wrinkle in Caltrain's existing plans, but those plans ought to be carefully re-examined in the context of a shared corridor with HSR.
Incompatible Caltrain and HSR platforms would have several crippling drawbacks for the peninsula corridor. The operational benefits of "any train, any track, any platform" are too great to ignore--perhaps even great enough to smash the bi-level paradigm and the low-boarding paradigm. Beware of unvalidated assumptions!