• Green Line Type 10 thread

  • Discussion relating to commuter rail, light rail, and subway operations of the MBTA.
Discussion relating to commuter rail, light rail, and subway operations of the MBTA.

Moderators: CRail, sery2831

  by devnull
 
Commuterrail1050 wrote: Fri Sep 02, 2022 9:03 am I’ll believe it when I see them for myself! I’m guessing they will look similar to the type 9 fleet. Did they mention if the doors would be the plug sliding or folding doors? Only asking because of the E branch setup sharing the road.
Plug doors, IIRC. They mentioned moving away from folding doors in order to enable raising the platforms by a couple inches to allow for truly level boarding.

Ideally they would use this as a forcing function to build real platforms for the street-running E branch stops (or, maybe just as likely, they won't address this at all until the Type 10's start arriving, and then they'll use it as an excuse to "temporarily suspend" the section of the E branch between Brigham Circle and Heath St)
  by typesix
 
Currently the folding doors will sometimes or many times catch on the raised platforms and require the operator to manually close them.
FYI the Type 9s will not MU with 7s or 8s.
  by The EGE
 
Yes, the plug doors are necessary to enable true level boarding, which is planned once the last Type 7 and Type 8 cars are retired. The T had a bad experience with plug doors with the Boeing LRVs, but that technology has come a long way since then. Virtually every second-generation (1981-now) light rail system in the US now uses plug doors with minimal issues. Modifying platforms will be relatively easy for the most part: add six inches of concrete, adjust elevator openings and stairs, etc. I'm curious to see how the transition will work - there will be a period where Type 10s are running and need the higher platforms for accessibility (they will likely not have built-in ramps like the 8s and 9s), but the 7s and 8s are still around. Likely there will be small sections of higher platform to serve a single door on the 10s.

The city is indeed working on a design for the Brigham Circle - Riverway section of Huntington Avenue. A very early render showed side-running tracks, which is bad for both trains and bike, and they very quickly reversed course and indicated that center-running would be kept. My best guess is there will be dedicated bus + train lanes, with an accessible stop at Mission Park; making Riverway accessible will be trickier.
  by typesix
 
The 10s will have bridge plates like the 8s and 9s.
  by bostontrainguy
 
typesix wrote: Mon Sep 05, 2022 2:10 pm The 10s will have bridge plates like the 8s and 9s.
Why would they have bridge plates if the loading/unloading will all be at true level platforms? They wouldn't even be able to extend them not to mention how problematic they are.
  by RandallW
 
For "level boarding", bridge plates are needed if the gap between the car and the platform is more than 3" horizontal and 5/8" vertical.
  by typesix
 
The rapid lines are still using bridge plates.
  by MBTA3247
 
The bridge plates may only be needed as a temporary measure until all the platforms can be rebuilt. Modern streetcars with true level-boarding that I've seen don't use them, as the platforms are positioned close enough to the track to not need them (some do have door thresholds that extend an inch or two out from the carbody, but those are fixed in place)
  by ExCon90
 
The EGE wrote: Mon Sep 05, 2022 1:24 pm The T had a bad experience with plug doors with the Boeing LRVs, but that technology has come a long way since then.
At the time the Boeings were operating there was word going around (true? urban legend?) that the plug doors had over 300 moving parts -- don't know whether that was per door or per car. I always felt that the Boeing people were accustomed to the aerospace environment in which the missile is highly complex and has to work perfectly -- once; everything has to be exactly right and if necessary you postpone the launch, with technicians crawling all over the thing, until everything is. Just the opposite in the transit industry, where the correct number of cars has to be ready to go every day and you can't tell thousands of commuters that the "launch" is postponed until tomorrow or next week.
  by typesix
 
It was reported that the original Boeing plug doors had about 300 parts/door compared to about 50 parts/door for a PCC.
  by MBTA3247
 
Perfectly good plug doors existed when the Boeings were built, but Boeing refused to license any existing designs and instead came up with their own, which was infamous for being far more complicated and failure-prone.
  by jwhite07
 
Boeing also decided to come up with their own articulation design rather than using existing designs (such as Duwag's), which was also unnecessarily complex and turned out to be rather fragile. Articulations of any design have been an Achilles heel here. Bad things tend to happen to articulations during even minor derailments and accidents, and cars have sometimes sat out for years awaiting repair of articulation damage.

I'm not advocating a return to short, non-articulated PCC or CLRV style cars. It was laughably predictable, however, that in typical more-gadgets-are-better fashion, the two final choices for design of the Type 10 were for 5 section or 7 section cars, and the choice made for the Type 10s is the 7 section car. That's 6 articulations/points of potential failure. Given the well established history here on this network, what could possibly go wrong?
  by RandallW
 
That's the Federal Contractor way, unless the contract specifies delivery targets or there are other regulatory constraints that encourage or require the licensing of existing designs or components, you do it yourself on the customer's dime and expect the customer to pay for every the designing of every fix.

(It's not that Boeing was used to building to rockets, its that (at least this part of) Boeing was used to operating in a contracting environment that was willing to spend a seemingly unlimited to amount of money to fix things later.)
  by R36 Combine Coach
 
jwhite07 wrote: Tue Sep 06, 2022 6:29 am I'm not advocating a return to short, non-articulated PCC or CLRV style cars.
The single unit 1981 Kawasaki cars at SEPTA have run well after 40 years in part to simplicity, basic engineering
(specified by the procuring agency and not the builder) and were intended as a modern take on the single unit
PCC concept. Even they have lasted better than PCC-II rebuilds with modern technology.

The Type 7s were successful since 1987 as well.
  by BandA
 
If the trolleys were behind fare gates it wouldn't matter if they had articulating sections and pass-through, or if they were 5 car PCC consists. If you expect the motorman to also collect fares you need long vehicles with pass-through