Green Line Extension Lechmere to Medford

[Arlington]

I don't understand why the GLX is attached to the green line rather than the orange line. Orange line cars are a much better form factor than the type 8 kludge. And since they are building all new grandiose stations, there is no benefit or cost saving for low boarding.

(I'm going to come down in favor of doing the extension as Green, but the case for the Orange Line is very strong, and the process that resulted in Green was kind of haphazard)

There was a great discussion about the Orange Line that mostly agreed with you--someone made the point that with shorter headways (upgraded signals) the Orange Line had as much capacity to "offer" beyond North Station as the Green Line did (but only if you gave up on it ever going north from Oak Grove to Reading)

And, worse, the heavy-rail-ification of the Green Line snuck up on them as the planning process unfolded. It was originally a $400m project that assumed D-Line stations (no headhouse, no faregates, no elevators/escalators). And IIRC, what favored Green over Orange in the planning was that Green was supposed to have a lower cost per rider because it was "light". But then they realized that it was likely to be a victim of its own success and need 3-car trains and pay-before-boarding, and yes, next thing you knew, stations had (somthing like) quintupled in price. There's definitely a case to make that had-they-known-in-advance that they were going to build "heavy" stations, it might very well have been Orange out the Lowell line.

But that was also a time when they knew they had to get to "Medford Hillside" but hadn't picked a route (they considered a single branch that'd have to tunnel from Union Sq to Gilman Sq). This also points out how silly the "mandates" that went with the big dig were--they basically enshrined the prejudices of railfans from the 1970 without regard to subtle shifts in public opinion and big technology changes (and the plummeting of auto emissions, the emergence of hybrid vehicles--and even diesel-electric / silver-line)

Working with the Green, it did seem that the branching that allows them to tap both the Fitchburg and Lowell ROWs seems more "natural" doesn't it? How would you have done it wit the Orange?

[Mcoov]

Tunnels. Tunnels everywhere.

[MBTA3247]

Tunnels. Tunnels everywhere.

Complete with subterranean waterfalls in the stations.

[Patrick Boylan]

Tunnels. Tunnels everywhere.

Complete with subterranean waterfalls in the stations.

I see nothing new.

[BostonUrbEx]

Lots of complaining about the need for sound barriers on the past couple pages.

It's actually not so much for the Green Line, but for the commuter rail, which will be shifted closer to housing. They are building the walls for the Green Line as well, mostly to appease any NIMBYs, but in some spots the distance between houses and booming commuter trains will be cut in half.

Frankly, I think the walls will just be ugly if they're 8+ ft tall. So, even with railfandom aside, I still wouldn't want anything more than others suggested (3 to 4 ft).

[CRail]

There's no commuter rail on the structure. As I stated before, I think those are the sound barriers that are bothering people (me, for example). When you're in a trench there's nothing to see anyways.

[ceo]

As someone who lives close to the Lowell ROW and a former Orange Line commuter, I expect an Orange Line extension up this way would have met with a lot more opposition... not for the scary-brown-people reasons (though I'm sure there'd be some of that too, sadly), but because the Orange Line trains are [i]horribly[/i] loud. Maybe not quite as loud as the commuter rail, but there'd be a lot more of them.

[joshg1]

As to why Green and not Orange, I think in terms formerly used to define rapid transit plans: low platform and high platform. Obviously Green is low platform, and in the 1940s it was thought there would be more lines like the D branch, not all feeding the central subway. Headhouses and prepaid platforms aside, am I right in thinking building a low platform line (shorter platforms, catenary) cheaper than a high platform line? I'm thinking surface line v. surface, not surface v. tunnel.

[deathtopumpkins]

As to why Green and not Orange, I think in terms formerly used to define rapid transit plans: low platform and high platform. Obviously Green is low platform, and in the 1940s it was thought there would be more lines like the D branch, not all feeding the central subway. Headhouses and prepaid platforms aside, am I right in thinking building a low platform line (shorter platforms, catenary) cheaper than a high platform line? I'm thinking surface line v. surface, not surface v. tunnel.

If we only look at platform height, and not headhouses and fare control, then I'd imagine low platforms are only minimally cheaper than high platforms. There's still a platform, it just doesn't have quite as much concrete underneath, which is negligible given that IIRC platforms are usually hollow boxes anyway.

Honestly the way they're building this extension on a grade-separated right-of-way, with all prepaid stations and fairly decent distances between stations, it sounds almost a waste to run the green line on it. Swap the catenary for third rail, raise the platforms, and bam you've got a new subway line. You don't have any of the things that make light rail more attractive, like the ability to run in the street, and eliminating the need for fare control.

[CRail]

You're forgetting about the vehicles used. Firstly, regardless of platform height, the length is significantly different between heavy and light rail. Station spacing plays a role, although they're not particularly dense on the extension RT stations typically have good distances between them (someone forgot to mention that to the Assembly Sq. people). I will add that downtown is an obvious exception but between line transfers and significant concentration (which is a typical feature of a downtown) it makes sense.

The other difference is capacity. The terms heavy and light refer to the ridership, not the vehicles. While I certainly expect this corridor to see substantial use, it isn't fed the way the RT lines are. North of Lechmere, there won't be stations like Harvard, Davis, Central, Malden, Wellington, or Sullivan with surface lines dumping busloads of transfers by the minute. This line is designed for those who actually live around it.

[Mcoov]

The other difference is capacity. The terms heavy and light refer to the ridership, not the vehicles. While I certainly expect this corridor to see substantial use, it isn't fed the way the RT lines are. North of Lechmere, there won't be stations like Harvard, Davis, Central, Malden, Wellington, or Sullivan with surface lines dumping busloads of transfers by the minute. This line is designed for those who actually live around it.

I imagine that within the next 20 years, that's going to change. New bus routes will be implemented that will link up with the GLX, especially at Union Sq., and before you know it, Green Line ridership could potentially double.
That assumes the T is competent, which sometimes they are.

Ultimately, I'm sad that GLX is not street-running. Even if logistically it's more of an issue, all the feature creep with prepaid headhouses and whatnot would not be an issue.

[The EGE]

GLX street-running would have been a nightmare. Somerville's main arteries aren't terribly wide; you couldn't get dedicated lanes or medians. So you're running at or slower than the existing buses, along pretty mediocre routings. The service would be no better than increasing bus frequencies, and it wouldn't allow further extensions because of the slow trip times. Plus, it would just make schedule reliability on the Green Line one step further into disaster.

The chosen routing - while not perfect - is pretty good. It gets two branches to most of the worthwhile spots in Somerville. Those two branches mean Lechmere finally gets double frequency service, and they provide future extension potential to Porter/beyond and West Medford/beyond. Using existing railroad right-of-ways means barely any land-taking while not having to fight residents and businesses about parking.

[octr202]

I'm trying to remember if/when the concept of an Orange Line branch ever came up in the planning process. I had some involvement back in the Alternatives Analysis phase circa 2005-2006, and at that point only Green Line options were being vetted against BRT, Commuter Rail and no-build options.

At one point, consideration was given to extending the Blue Line into the GLX corridor. Operationally that had a lot of potential to take advantage of the BL's current downtown terminus, but the costs of tunneling under the West End made it a non-starter. Unfortunately I can't locate the documents where I once saw this Blue Line proposal.

[The EGE]

The Blue Line extension was in the 2004 PMT. It was then to cost $697M and get 13,500 riders (5800 new), versus $375M and 8400 riders (3500 new) for the Green Line. The supposed difference in ridership was due to faster travel times, but that seems to neglect that the Green Line goes to a lot of areas that the Blue Line doesn't.

[octr202]

Thanks, EGE. I knew I'd seen the Blue to West Medford concept somewhere. Nice to know I'm not making up memories yet.