As you probably know, Caltrain and the CHSRA are supposed to share infrastructure but can’t agree on a common platform height. The CHSRA train specification is for 1295mm (51″) floor height, That is much too high for Caltrain with its legacy 8″ platforms.
If you are wondering where the CHSRA came up with the 51″ number, the answer is that it was mainly a political decision. The FRA wanted California to use HSR rolling stock compatible with the NEC corridor (even though the NEC is thousands of miles away). When that idea proved impractical, the joint bid was dropped. And yet here we are, apparently stuck with the 51″ requirement.
What needs to happen now is for the CHSRA to drop the 51″ requirement from the train specification. Since Caltrain and the CHSRA will almost certainly use European “off-the-shelf” trainsets, the obvious solution is to follow the European platform standard.
In 2002, the European Commission issued a Technical Specification for Interoperability (TSI) that allows for two possible platform heights: 550mm and 760mm. If you do the metric-English conversion, you find that 550mm is 21″, and 760mm is 30″. For comparison, Caltrain’s Bombardier cars have a 25″ floor level. So trains built to either the 550mm or 760mm platform height would provide backwards-compatibility to legacy 8″ platforms while the agency works on rebuilding platforms to the new height.
Following the TSI platform standard is also in the best interests of the CHSRA, because it will ensure the largest number of vendors can bid on high-speed train procurements. In a 2009 white paper, the CHSRA planners tried to argue otherwise, saying that most HSR trains currently in operation fall within the range of a 45″-51″ height. That is certainly true, but they need to think about the state of the market in the year 2024 (when California’s system supposedly begins operation), not the year 2009. It is clear that the next-generation of HSR trains are going to be compliant with TSI accessibility standards.
In fact, most vendors have already made the switch to TSI standards. Talgo, for example, offers two HSR trains with low-floor coaches at the 760mm height:
Talgo 760mm level-platform boarding
Euroduplex 550mm entrance
The new Stadler EC250 is also low-floor. It will operate on new high-speed service between Zurich, Frankfurt, and Milan, though only with a maximum speed of 155mph.
The TGV duplex is yet another train with 550mm level-platform boarding. Even though it is the workhorse of the TGV network, the CHSRA has already ruled out the use of this train, saying it has “unappealing aesthetics”. It is incredible that the CHSRA would so blithely dismiss Europe’s most popular high-speed train.
One HSR vendor that does not offer TSI-compliant trains is Siemens. Siemens does, however, have a train manufacturing facility in Sacramento and has made grandiose promises of local jobs if it wins the contract. This leads to the suspicion that specifications were written to favor a preferred vendor — at the expense of taxpayers and transit riders.
If the CHSRA prevails on using 51″ platform boarding, the implications would be quite bad for Caltrain. There would be no good options for migrating to that platform height. Caltrain would either have to decide on segregated platforms for HSR (limiting its access to the new Transbay Terminal) or else design some goof-ball train with two sets of doors.
Sadly, it appears Caltrain is going with the latter plan. In a presentation last month to San Francisco officials, Dave Couch of Caltrain outlined a plan whereby the new electric railcars would have dual sets of doors. One upper set for stations with 51″ platforms, and a lower set of doors for the legacy 8″ platforms. This is a huge step backwards from what customers have today. At least with the current rolling stock, riders only have to make one (small) vertical transition. The new rolling stock would add yet another — inside a crowded moving train, no less, where there are also bikes and luggage to contend with. To accommodate wheelchairs, some kind of internal wheelchair lift may be needed too. And a train with dual sets of doors isn’t exactly off-the-shelf, so expensive customization would be needed.
This proposal is so ridiculous, it is hard to believe it is being taken seriously. Let’s hope it leads to a re-evaluation of the CHSRA platform decisions.
Systemic Failure 
“The largest number of vendors”? No. First, two thirds of the world’s HSR ridership is in China and Japan, which have 1,250 mm platforms. Second, the remaining third, mainly in Europe, has trainsets that for the most part have floors in the 1,200 mm region, with non-level boarding. It’s true that European vendors are moving toward level boarding to lower floors, but so far the only >250 km/h examples are the Talgo, which has dedicated power cars (i.e. less capacity), and the TGVs, where dedicated power cars and the Duplex’s bilevel configuration cancel each other out, giving the same capacity as a single-level Velaro or Zefiro set. Compare this with the number of existing and under-development sets with high floors – AGV, Zefiro, Velaro, Oaris, anything coming from China and Japan.
Finally, Caltrain can actually migrate to high platforms easily, if it’s willing to endure a short-term kludge of trains only opening the doors of some of the cars (as practiced every day on Metro-North). It can rebuild half the length of each platform before beginning the transition to high-floor EMUs, and then rebuild the other half after the transition is complete. Current trains have 5 cars and current platforms are mostly 7-car long, so this means 3 open cars per 5-car train, requiring people to walk forward or back at most one car. And of course 4th and King has a surplus of platforms, so it could have full-length high platforms alongside full-length low platforms during the transition.
FWIW, please note that the TSI platform height standards do not imply that compatible train sets necessarily have floors at a specific level. For example, the TGV Duplex lower floor is actually at 314 mm, the cars have an internal step down from 550 mm platforms.
On the dedicated wheelchair cars, the floor has a lift that raises it to platform level. As you can see in the image, it allows level boarding.
However, California may not need such a contraption. The reason for the steps down was because of the tight height constraints of the legacy rail network in France. California does not have that problem, so one option would be to raise the suspension and do away with the steps. Because of Buy-America rules, these trains will be heavily modified anyway.
Talgos have had 30 inch floors since decades before TSIs were dreamed up in Brussels.