At today’s Caltrain board meeting, at modernization update presented by project lead Dave Couch, Caltrain disclosed new information about the technology compromises that could enable platform compatibility with High Speed Rail, and efforts to accelerate funding for compatibility and increased capacity.

Two options for customized cars are being considered – a two-door car that would serve platforms at two heights, and a “trap door” mechanism that would move to serve the two platform heights.    The two choices have different benefits and drawbacks. The “double door” approach would be mechanically simpler, but would allow fewer seats per train (see last paragraph for estimates). The “trap door” approach would not reduce passenger capacity, but would increase reliability risk by adding customized moving parts.  The double doors would enable Caltrain to serve current low platforms, and new higher platforms compatible with high speed trains.

To compensate for the reduction in train capacity, Caltrain and High Speed Rail are talking to MTC and the financial partners in the blended system, for a plan to accelerate a package of additional investments to increase capacity, including 8-car trains, platform updates to allow for 8-car trains and level boarding, and replacing the remaining 25% of diesel cars that were expected to keep traveling the corridor from San Francisco to San Jose, because of insufficient funding to fully electrify.  These improvements would add more than 33% additional capacity (more than the increase in going from 6-8 car trains), since fully electric service and level boarding would allow Caltrain to run a more optimized schedule that could carry more passengers.

The capacity lost to a double-door system would presumably be eventually regained, once Caltrain has updated all of its platforms to the new height.  At that time, the extra door would be closed up and potentially seats could be added back.

A full evaluation of the benefits and tradeoffs for the board would logically consider the additional blended system capacity provided by Caltrain/HSR compatibility; the additional capital and operating costs and medium-term capacity impacts of compatibility; the dwell time and schedule implications of the nonstandard car design; and an overall schedule for a transition to level boarding and restoring the lost capacity.

The reason that Caltrain and High Speed Rail are considering compatible platforms is because compatibility will increase longterm capacity of the “blended system” with Caltrain and high speed rail at shared stations, especially the space-constrained Transbay terminal, which is expected to be the single most heavily used station on the Caltrain line. (Of course, passengers who use Transbay will also use other stations, so increased ridership at Transbay will mean increased overall ridership and fewer cars on the freeways).

Several public comments at the board meeting expressed concerns that Caltrain may be compromising its service for the benefit of High Speed Rail.  The board and stakeholders will need to consider the compromises, and also the amount of long-term increased capacity and operational improvements that would be gained with compatibility.

At the board meeting, Director Nolan asked for a board workshop to review the full consequences of these decisions that will shape the system for many decades, and GM Hartnett agreed.  A board workshop would happen later this spring, to help the board make decisions for the RFP that is scheduled to be issued this summer.

(The double-door approach would reduce seats by 78-188 seats per train.  Today’s 5-car trains carry ~620 – 680 passengers; the electric trains would be 6-car trains; so the 2-door trains would provide very roughly 10-20% less passenger capacity, depending on a variety of decisions relating to space for bathrooms, bikes on board, and standees.)