Green Line Extension to Medford & Union Sq

DBM said:
I saw on wikipedia that these trains will max-out at 50 mph (which I assume is the same for the entire Green Line, then?). Measuring the the extension as being almost exactly 5 miles from Tufts to Park St., at first that sounds pretty good--5 miles @ 50 is 6 minutes.

BUT: 8 intervening stops. Let's say 1 minute on average to complete deboarding/boarding for all 8 stops. So that's 8 minutes.
AND: acceleration/deceleration is considerable when there's 8 stops crammed into a mere 5-mile segment. So realistically the trains will average 25 mph? so that would be 12 minutes.

So that combines to a 20-minute average ride from Tufts to Park Street, if the calculations are right--which sounds pretty competitive compared to, well, everything, unless you're a great cyclist (and even then there are all the miseries and unpleasantries and hazards of biking @ 15 mph constantly through the asphalt jungle that is Tufts--Park corridor).

But would it in fact be longer than 20-minute on average? Am I undercalculating due to other factors? Should we allow for more than one minute to complete each stop's boarding/deboarding cycle? I don't think I've seen this computation on this thread (apologies if it's been done already), so I'd love to see someone else's arithmetic if I have it wrong.
Click to expand...

8 intervening stops? It's 9 by my count unless I'm misreading the station list.

It's unscientific, anecdotal, and somewhat dated, but back when I was a regular Green Line rider, my rule of thumb in the Central Subway (presumably extendable to the GLX, which does not have the traffic lights that mess with the surface branches) was roughly two minutes per stop (not including my origin and destinations, which were budgeted at one minute). This was a good decade ago, but it was pretty consistent (albeit not necessarily at peak times). Between the Type 7s' stairs and the awkward configuration of the Bredas (I don't know about the Type 9s, but the cab-end door of the Type 8s is appallingly awkward), GL trains can spend what seems like a while on the platform.
 
I agree that 20 mins is a good estimate

Riverside to Kenmore is 13 stops in 28 minutes (Saturday morning on Google Maps). So I’d swag GL “single branch surface trips” at 2 mins per stop (after origin)

That’d swag Medford to North station at 14 minutes. And North to Park is 6 minutes. So I’d say the whole trip is 20.
 
Brattle Loop said:
8 intervening stops? It's 9 by my count unless I'm misreading the station list.

It's unscientific, anecdotal, and somewhat dated, but back when I was a regular Green Line rider, my rule of thumb in the Central Subway (presumably extendable to the GLX, which does not have the traffic lights that mess with the surface branches) was roughly two minutes per stop (not including my origin and destinations, which were budgeted at one minute). This was a good decade ago, but it was pretty consistent (albeit not necessarily at peak times). Between the Type 7s' stairs and the awkward configuration of the Bredas (I don't know about the Type 9s, but the cab-end door of the Type 8s is appallingly awkward), GL trains can spend what seems like a while on the platform.
Click to expand...

Yep, my miscount! Nine stations... 2 minutes certainly seems like a good rule-of-thumb for peak rush hour. But I was envisioning during non-rush hour. To get, say, 15 able-bodied individuals on, and 15 off, and opening and closing the doors, seems like a minute to me, just visualizing with my cellphone stop watch.

Ball Sq.
Magoun Sq.
Gilman Sq.
East Somerville
Lechmere
Science Park
North Station
Haymarket
Gov't Ctr
 
fattony said:
I’m not an expert, but 1 minute sounds like a painfully long time to sit around with the doors open. I can’t imagine any stop before Park taking more than 20 seconds or so. Park is a special case of course.
Click to expand...
At most stations, at least in the Subway portion of the GL the doors are open between 15-20 seconds
 
The complaints about the timing is exactly why the green line needs a complete overhaul. I’m not sure how extensive the work or high the cost would be but it would be nice if the Green Line was converted to a traditional LRT (similar to LA) away from the Trolley like system.
 
NoShJFK said:
The complaints about the timing is exactly why the green line needs a complete overhaul. I’m not sure how extensive the work or high the cost would be but it would be nice if the Green Line was converted to a traditional LRT (similar to LA) away from the Trolley like system.
Click to expand...
"Traditional LRT" and "trolley like system" are terms without distinct definition. You're throwing them around like they're supposed to mean something specific and exacting, but they really don't. LRT is an extremely elastic classification, inclusive of both the Green Line and L.A.'s system (including the Metro lines that are "HRT in everything but name"). Say specifically what you mean here, because that nomenclature is almost meaninglessly anti-specific.

Quite a lot of timing things are being optimized with Green Line Transformation. Are you asking for one of the timing things already covered or not covered in the GLT project, for instance?
 
  • Like
Reactions: W-4
A48D1306-93C4-4FB2-ABF9-47E78C1F1807.jpeg

Starting to seal off the GLX from the Lowell Line ROW.
 
Surprised they're doing fencing before center cat poles in that stretch, and apparently also before outfitting the utility conduits (per the wood covers). Is this just a sample stretch to evaluate what the finished product is supposed to look like?
 
They have dumped a bunch of the same fence posts in the ROW north of Cedar St, so I think this is the final product.

The fence contractor is from Long Island, so maybe they have to get their work done in one batch.
 
F-Line to Dudley said:
Surprised they're doing fencing before center cat poles in that stretch, and apparently also before outfitting the utility conduits (per the wood covers). Is this just a sample stretch to evaluate what the finished product is supposed to look like?
Click to expand...
Looks to me that plywood allows the fence guys to stand on it and reach the top of the fence as they install it otherwise they have to work on the live track. . Maybe they are afraid they will damage the permanent covers or maybe the covers aren't available yet? Ballast obviously needs some dressing up too.
 
reno said:
Looks to me that plywood allows the fence guys to stand on it and reach the top of the fence as they install it otherwise they have to work on the live track. . Maybe they are afraid they will damage the permanent covers or maybe the covers aren't available yet? Ballast obviously needs some dressing up too.
Click to expand...
There's a ton of electrical and signaling plant that's going to periodically shoot out of the conduit, so they probably haven't even unloaded the permanent covers yet. Since they don't even have the center poles mounted they're a long way from done with the utility work there.

All-around strange finishing sequence on this segment.
 
F-Line to Dudley said:
All-around strange finishing sequence on this segment.
Click to expand...
I'm feeling the strangeness is "odd but not absurd" since a fence between the GLX and Lowell Line of some sort is required by the FRA basically everywhere whenever the Lowell Line is operating, right? (or, if not present, then the trains would have to crawl, be flagged, or blow their horn more than the neighbors could tolerate)

At various points we currently have either jersey barriers or lumber-and-chainlink (as seen in the photo), so the center poles were going to be installed in a "fency" environment either way. But now instead of temporary (and removeable) fencing it is permanent (or as permanent as chain link allows).
 
The ROW between Broadway and Cedar has foundations for fencing along the centerline north of where the concrete barrier ends, so I think we are seeing the real barrier installation.
 
Why is the fence needed, are they worried the green line train might get confused and try to change tracks?
 
jass said:
Why is the fence needed, are they worried the green line train might get confused and try to change tracks?
Click to expand...
Separate modes, separate dispatchers, and separate work windows by mode for Maintenance of Way staff. Saves a large amount of coordination when rapid transit's night work shift could be out any overnight on the week but Keolis uses the wee hours to stage some trains to the outer layovers and/or Pan Am very occasionally sends its Lawerence-Winchester overnight freight inbound to do spot mop-up work in Somerville. Unless it's a rare occasion where the specific work task spans the fence, on a physically sealed corridor they wouldn't need to coordinate at all with the CR side to do their thing. That saves resources. Commuter Rail MOW is more likely to be on weekend shifts rather than overnight, so similar economies for them in staying on their side of the fence not triggering any cross-coordination with Rapid Transit Div.

Also comes in handy if a disabled train needs to be evacuated, in that you don't have to shut down both modes at once with passengers sticking to their side of the fence while out.


There's a lot of red tape informing it too. Feds/FRA on the RR side of the fence, and wanting to keep their onerous regs off the rapid transit side...plus totally alien track worker unions & regs on each side. But the genuine efficiencies for not having to coordinate work windows make physical separation well worth it in the end.
 
Lots of community path progress. This is looking outbound from the cross st bridge. The ramp down to the community path is making good progress and now they’ve poured out the actual path. It continues in the other direction almost to the Washington bridge.

3C6A7E2F-6AEB-4692-A25C-09A7623C0FB6.jpeg
 
jcunion said:
Lots of community path progress. This is looking outbound from the cross st bridge. The ramp down to the community path is making good progress and now they’ve poured out the actual path. It continues in the other direction almost to the Washington bridge.

View attachment 14847
Click to expand...
I wonder if they'll be able to open the path before the actual T if it's finished while the new rail system is being tested and finalized.
 
You must log in or register to reply here.

Back
Top