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Old 04-04-2018, 06:25 PM   #5141
millerm277
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Re: General MBTA Discussion Thread

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Originally Posted by jass View Post
I remember someone arguing that the SL would run just as quick (slow?) on surface streets

That person got their wish.

http://www.universalhub.com/2018/cei...rompt-shutdown
If they can't reopen it for tomorrow/Friday, it's going to be an impressive disaster over there.

PAX East begins tomorrow. And Michelle Obama is speaking at the Seaport Hotel.
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Old 04-04-2018, 06:27 PM   #5142
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Re: General MBTA Discussion Thread

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If they can't reopen it for tomorrow/Friday, it's going to be an impressive disaster over there.

PAX East begins tomorrow. And Michelle Obama is speaking at the Seaport Hotel.
The tunnel was scheduled to be closed this weekend to begin with, even despite PAX. Really bad planning just got worse.
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Old 05-01-2018, 04:00 PM   #5143
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Re: General MBTA Discussion Thread

Yesterday's FMCB meeting has some items regarding commuter rail visioning and Red/Blue (not linking directly since the slides were posted as powerpoints).
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Old 05-07-2018, 02:49 PM   #5144
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Re: General MBTA Discussion Thread

T planning $3.5b Green Line train of future

Had no idea the Lechmere viaduct was in such bad shape.
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Old 05-07-2018, 04:12 PM   #5145
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Re: General MBTA Discussion Thread

Not surprised. The MTA just had to completely rebuild a viaduct that was built in 1912... I think Lechmere dates from around the same time. Keep in mind trains are much heavier today.
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Old 05-07-2018, 06:40 PM   #5146
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Re: General MBTA Discussion Thread

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T planning $3.5b Green Line train of future

Had no idea the Lechmere viaduct was in such bad shape.
Iím confused. We have new green line trains due just a few years away, and these new new trains in 2028...

Does this make sense to anyone else?
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Old 05-07-2018, 06:56 PM   #5147
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Re: General MBTA Discussion Thread

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Originally Posted by DominusNovus View Post
Iím confused. We have new green line trains due just a few years away, and these new new trains in 2028...

Does this make sense to anyone else?
someone correct me if i am wrong---We only ordered 24 of the new trains to supplement the fleet for GLX. This article seems to be talking about the order after these deliveries.
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Old 05-07-2018, 07:03 PM   #5148
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Re: General MBTA Discussion Thread

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Originally Posted by DominusNovus View Post
Iím confused. We have new green line trains due just a few years away, and these new new trains in 2028...

Does this make sense to anyone else?
The Type 9s are actually due sooner than that. They're not meant to innovate on the Type 7s or Type 8s, just add to the fleet size to allow GLX to function. They're essentially identical to the Type 8s, just more reliable.

This new Type (likely Type 10) is an entirely different animal, and much of the $3.5B goes toward infrastructure improvements that allow them to be fundamentally unlike the current fleet. This is not only new vehicles - it's a reinvention the Green Line to make it more like a heavy rail line in places.

Whole presentation:

https://cdn.mbta.com/sites/default/f...n-overview.pdf

https://cdn.mbta.com/sites/default/f...e-capacity.pdf

https://cdn.mbta.com/sites/default/f...management.pdf
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Old 05-07-2018, 07:29 PM   #5149
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Re: General MBTA Discussion Thread

Quote:
Originally Posted by DominusNovus View Post
Iím confused. We have new green line trains due just a few years away, and these new new trains in 2028...

Does this make sense to anyone else?
Absolutely: By 2028, it'll be time to start phasing out the Type 7s (oldest will be 40 years old, some 30 years, most 10+ since overhaul and all "high floor"), while the Type 8s will be 20 ~ 30 years and not worth overhauling.

So the Type 10s are going to be a complete re-fleeting, so it'd be nice to get features like: all low floor, more open designs, and One (or zero) operator per more passengers, and the ability to operate at higher speeds.

On world-standard light rail, you get things like the ability to roll a bike, stroller or wheelchair in 1 door and out another (never having to U-turn inside the car). And you get more door boarding through wider doors (shorter station dwells)

It'd nice to have a lot of bidders with service-proven designs, where competition and standard designs can lower both price and design risk (whether the T or Breda's fault, the Type 8s were a huge pain because they were custom and low-floor was new-to-Boston. All-low-floor and long, articulated trainsets pose a similar risk if too non-standard)

If there's a pinch point (sharp curve) that's been both limiting speeds and dimensions, there might be a triple win in fixing it: more manufacturers with conforming designs, higher capacity trains, taking turns faster.

Even if they decide not to fix any curves or humps, there's still length considerations (at the short stations they name) and weight considerations (on the Lechmere Viaduct).

So it favors thinking in terms of infrastructure-and-rolling-stock packages.
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Old 05-07-2018, 09:14 PM   #5150
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Re: General MBTA Discussion Thread

Some thoughts from the slides:
  • Improvements to B and C to allow 2 type 10 cars will be part Phase IV which is at least 12 years out and mentioned as a "long term possibility"
  • This means that B and C will be limited to single 10 or dual type 9 trains for at least several years, possibly indefinitely.
  • Though the listed capacity for a single hypothetical type 10 is only 8 less than 2 type 9s (which, iirc puts them on par with the current type 7&8 trains) so not really a loss.
  • There's several slides about how the C-Line track width is currently too narrow, and it suggests center island platforms to allow for increased track width without forcing wheelchair users too close to the road when using the bridgeplate. Does anyone why the track width is an issue? If it was that it's too for type 10s then how is there any possibility of using type 10s before Phase IV? Or is the plan to widen the tracks during phase I and deal with the narrow platforms (since the stations where it'd be an issue aren't wheelchair accessible)?
  • There's a suggestion that they want more room to park trains at Riverside, but the planned redevelopment there will cause issues with this.
  • No mention of what the plan would for type 9s after phase IV, when they would be wholly obsolete, but could have well over a decade left in their lifespan.
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Old 05-08-2018, 09:01 AM   #5151
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Re: General MBTA Discussion Thread

Quote:
Originally Posted by Equilibria View Post
The Type 9s are actually due sooner than that. They're not meant to innovate on the Type 7s or Type 8s, just add to the fleet size to allow GLX to function. They're essentially identical to the Type 8s, just more reliable.

This new Type (likely Type 10) is an entirely different animal, and much of the $3.5B goes toward infrastructure improvements that allow them to be fundamentally unlike the current fleet. This is not only new vehicles - it's a reinvention the Green Line to make it more like a heavy rail line in places.

Whole presentation:

https://cdn.mbta.com/sites/default/f...n-overview.pdf

https://cdn.mbta.com/sites/default/f...e-capacity.pdf

https://cdn.mbta.com/sites/default/f...management.pdf
Interestingly, the documents don't note the Boylston curve as one of the infrastructure restrictions. Is this because it's not as severe as we think (and the screeches come from suboptimal engineering) or because it'll never be solvable and we just have to live with it?

Quote:
Originally Posted by Arlington View Post
Absolutely: By 2028, it'll be time to start phasing out the Type 7s (oldest will be 40 years old, some 30 years, most 10+ since overhaul and all "high floor"), while the Type 8s will be 20 ~ 30 years and not worth overhauling.

So the Type 10s are going to be a complete re-fleeting, so it'd be nice to get features like: all low floor, more open designs, and One (or zero) operator per more passengers, and the ability to operate at higher speeds.
Your description reminded me of a couple points in Apple's history that signaled new directions: Mac OS X and the iPhone X (both pronounced "ten", not like the letter "X"). Looks like the MBTA is thinking the same thing

Last edited by 34f34f; 05-08-2018 at 09:22 AM.
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Old 05-08-2018, 09:24 AM   #5152
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Re: General MBTA Discussion Thread

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Originally Posted by 34f34f View Post
Interestingly, the documents don't note the Boylston curve as one of the infrastructure restrictions. Is this because it's not as severe as we think (and the screeches come from suboptimal engineering) or because it'll never be solvable and we just have to live with it?
I learned recently that despite the public perception, the Boylston curve is nowhere near as bad or prohibitive as most think or suggest.

EGE actually wrote about it in a paper: https://dspace.mit.edu/bitstream/han...pdf?sequence=1

Quote:
"West of Boylston station, there is a tight, nearly-right-angle curve between Boylston
Street and Tremont Street, where both tracks cross over a former branch to the south.
This curve has minimum radii of 80 feet westbound and 90 feet inbound, causing a speed
restriction and wheel squeal that is audible from outside the station. Although the public
commonly perceives this as the tightest curve on the Green Line ó and the wheel squeal
issue certainly bears separate investigation ó it would actually require little or no modification
to meet the minimum radius of off-the-shelf vehicles"
Boylston is not bad at all. It's like 90 feet, which is not unusual for light rail systems. Park St loop is not the worst curve either. Lechmere inner loop is.
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Old 05-08-2018, 10:06 AM   #5153
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Re: General MBTA Discussion Thread

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Originally Posted by datadyne007 View Post
Boylston is not bad at all. It's like 90 feet, which is not unusual for light rail systems. Park St loop is not the worst curve either. Lechmere inner loop is.
And both the Lechmere inner loop and the Lechmere viaduct are already being replaced by GLX work.
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Old 05-08-2018, 10:06 AM   #5154
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Re: General MBTA Discussion Thread

I suspect (and hope) the cost and logistics of upgrading 27 B and C line surface stations will force some hard choices on stop consolidation.
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Old 05-08-2018, 10:09 AM   #5155
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Re: General MBTA Discussion Thread

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Old 05-08-2018, 10:17 AM   #5156
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Re: General MBTA Discussion Thread

The "Capacity" PDF lists the current worst curves (all less than 50' radius) on page 13 of 84

rad location Name
42 Lechmere Inner Loop (superceded by GLX)
45 Reservoir Yard West Wye Curve 97
45 Lake St Yard Curve 16
45 Lake St Yard Inner Loop
45 Lake St Yard Curve 13
47 Park Street Park St Loop
49 Government Center Brattle Loop

The great thing about all the 45s is that they're in yards (and the report proposes replacing them with 80'-ish curves)

For Park, the question is can more be sent to turn at Gov't Ctr (outer) loop?
If longer trains have shorter dwells, it seems possible that you'd send today's Park St turns to loop on the outer loop at Government Center (or re-make the Brattle loop's leads as pockets for reversing similar to the North Station setup)
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Old 05-08-2018, 11:11 AM   #5157
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Re: General MBTA Discussion Thread

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Originally Posted by Arlington View Post
For Park, the question is can more be sent to turn at Gov't Ctr (outer) loop?
If longer trains have shorter dwells, it seems possible that you'd send today's Park St turns to loop on the outer loop at Government Center (or re-make the Brattle loop's leads as pockets for reversing similar to the North Station setup)
I think that is the intention. If you look at page 17 they are leaving the Park St. Loop at 47 ft. but putting a bypass in so that eastbound trains can use the center platform but bypass the loop and continue on towards Government Center. Currently trains in that center platform can't proceed to Government Center, and this would fix that.
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Old 05-08-2018, 11:16 AM   #5158
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Re: General MBTA Discussion Thread

So the single-platform approach is still the "MBTA preferred approach" to reconstructing all three Newton stations? Why bother spending the money if there's only going to be a single platform serving one track?

https://cdn.mbta.com/sites/default/f...ter-newton.pdf
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Old 05-08-2018, 11:29 AM   #5159
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Re: General MBTA Discussion Thread

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So the single-platform approach is still the "MBTA preferred approach" to reconstructing all three Newton stations? Why bother spending the money if there's only going to be a single platform serving one track?

https://cdn.mbta.com/sites/default/f...ter-newton.pdf
I think the first thing that mattered was which track the side platform was on (the initial plan picked the wrong one, IIRC), I kind of remember that "single-platform but on the other side" was the conclusion. Maybe that's what they're proposing?
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Old 05-08-2018, 11:41 AM   #5160
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Re: General MBTA Discussion Thread

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Originally Posted by 34f34f View Post
Interestingly, the documents don't note the Boylston curve as one of the infrastructure restrictions. Is this because it's not as severe as we think (and the screeches come from suboptimal engineering) or because it'll never be solvable and we just have to live with it?
This was always a stupid excuse.

Note that in the diagram, the X cars have 6 articulation points, versus the current vehicles that have 2.

Thats all you need, more articulation joints where the car can "spin"



Thats why you can have a 50-car train make the same turn as a 1 car train. The overall length is not an issue.
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