The Original Plan
To maximize the short-term seating capacity of the new trains until the 2030s, Caltrain specified that the intermediate level should have temporary flip-up seats installed in front of the unused doors, five per door vestibule, with the seating blocking off the doors like this:
|Configuration of intermediate level in A, B, C, E, and G cars
At some undetermined future date when the intermediate doors would be needed for compatibility with high platforms, the blue flip-up seating modules would be removed from the intermediate level.
A Regulatory Conundrum
In the design of any new train, federal safety regulations require that any passenger seating compartment be fitted with at least two emergency exit windows (for passenger egress) and two rescue access windows (for first responder ingress). The intermediate level counts as a passenger compartment because these flip-up seats are located within it. However, the intermediate level does not have what regulations consider to be a window; the only opening to the outside is through the doors. This set up a conflict with safety regulations.
In late 2017, Caltrain petitioned the Federal Railroad Administration for a waiver (docket FRA-2018-0003) by arguing that the emergency release feature of the doors would provide an equivalent level of safety, despite not meeting the letter of the regulation, allowing emergency access by climbing over the seat backs.
In June 2018, the FRA denied Caltrain's request because the flip-up seating installed longitudinally such that it blocks the doors could impede egress and access and therefore did not meet the intent of the regulation. The FRA stated that "the absence of need for these intermediate level doors to support current revenue boarding and alighting requirements does not negate the necessity for an unobstructed path in the event of an emergency." Curiously, this unobstructed path requirement applies only to doors, not to windows!
Implicitly, Solution A is to remove all seating from the intermediate level of the affected cars, which effectively sidesteps the emergency window requirement. But given that seating in Caltrain's EMUs is already quite limited, this solution seems like a non-starter as it would reduce seating capacity of a 7-car train by 9% from 667 seats to just 617 seats.
|Solution A: not a passenger seating compartment
Solution B: equip the intermediate level doors with a regulation-size emergency window of minimum dimensions 26" wide by 24" high. Unfortunately, that is too large for the dual-leaf design of the train doors; in other words, the window in each door leaf is too narrow to function as an emergency window.
|Solution B: the minimum clear opening is too big for dual-leaf doors
|Solution C: doors replaced by plug panels
There are other solutions that strike a better balance of functionality and simplicity without a seven-figure cost impact.
Solution D: short of removing all the seating from the intermediate level vestibule, the regulations require only one emergency window (instead of two) if there are four or fewer seats in the compartment. Removing seats from one side only and applying for a new waiver to allow unobstructed use of one of the doors in lieu of a single emergency window could work, addressing the FRA's stated concern with door obstruction. This would reduce seating capacity of a 7-car train by just 22 seats or 3% (5 seats lost in cars A and B, and 4 seats lost in cars C, E and G).
|Solution D: reduced seating with unobstructed emergency access
|Solution E: change flip-up seating orientation to provide unobstructed door access
(flip-up seats are shown in use; they fold flush against wall when not occupied)
|Flip-up seats in a doorway of a brand new Bombardier EMU on Paris RER line D.
(foreground at left) credit: Wikipedia / KiHa 52
Ultimately, it is entirely possible that Caltrain simply does not wish to interface with high-speed rail in any station as a matter of policy, because it would require sharing and collaborating with another agency, and solving a somewhat complicated ADA compliance problem. Which agency would voluntarily bring that upon itself? Caltrain already took the HSR money, and installing plugs will "erase" the clunky and unpalatable concession they made in the name of compatibility, with the further bonus of not requiring another run at the FRA for a new waiver. The complicated ADA compliance issues associated with interior lifts are kicked as far down the road as possible!
No matter how you look at it, Caltrain's chosen approach is a ~$15 million mistake that reduces and complicates compatibility with HSR stations and platforms. There are cheaper, simpler and easier ways to achieve compliance with emergency window regulations. It's not too late to change course.