Green Line Extension to Medford & Union Sq

Some promising news. There is a paywall



The work will improve the 110-year-old structure in the short-term, shoring up arches and beams and allowing trains to move more quickly over it. But it also has longer-term ambition: making the viaduct strong enough to handle the next fleet of Green Line cars, which officials are designing to be twice as large as the current generation.

Does this mean there will be another rebuild for the next generation of Green Line Cars?
 
It is a relic. Welded rail and overhead wire are continuous across the former draw span, utility conduits have been laid under the tracks across it, and the machine room in one of the towers (which had a RR.net photo tour by late great BSRA officer Paul Joyce which I can't find at the moment) is derelict. Coast Guard maritime jurisdiction ends at the Charles Dam, so they were able to stealth-retire it some decades ago (after a much longer period of no openings) at no change to maritime regs and cap Charles Basin's height limit at the level of the closed position. I don't know when the last time was that it actually opened...probably well in excess of 50 years ago. The really narrow passage on N. Washington St. swing bridge + the North Station draws discouraged most tall-mast traffic before it ever got as far upstream as the Viaduct, so after about the first 15 years of operation when the North Station draws were all renewed to their modern equivalents the rate of Viaduct openings had already been slashed back to near-nonexistence.

Yeah, the utility conduits are visible on Google Maps "RiverView."
 
The biggest limiter on boats entering the Charles is the Charlestown Bridge, which hasn't operated as a drawbridge for decades and its replacement will be fixed-span. The Lechmere Viaduct drawspan is higher (I'm 90% sure), so there's no reason for it to open.
 
Yeah, the utility conduits are visible on Google Maps "RiverView."

Also, I'm pretty sure the draw span is welded shut such that you can't even bring a crane in to 'pop the top' today for a special move (assuming you could first get the N. Washington swing open to get that far upriver). Fact that the rail is continuous welded across the whole draw span is the tell there. If the draw were simply resting in the down position instead of hard-fused they'd need to have rail joints positioned above at the transition points to safeguard against thermal expansion/contraction from daily temperatures causing subtle alignment shifts on the trackbed. If there's not even that much allowance for movement anymore it is truly and permanently locked in-place.
 
What kind of reinforcement does the whole viaduct (drawspan or not) need? Will we see interior cross-bracing? Usually concrete structures are "more the merrier"
 
What kind of reinforcement does the whole viaduct (drawspan or not) need? Will we see interior cross-bracing? Usually concrete structures are "more the merrier"

Most of the needed weight reinforcement is going to the steel viaduct segment north of Gilmore Bridge out to where it's being cut for the transition onto the brand new GLX Lechmere elevated. That's much flimsier-construction than the concrete portion, and a weight concern every time they order a new vehicle generation. The concrete Viaduct is massively overbuilt for its needs and probably doesn't need much more than a concrete-patch refresh for new wear that's exposed itself since the last patch job in '04.

I wonder if they'll use the shutdown to round up the Science Park platforms to Type 10 vehicle length. Inbound platform needs to be topped off by +5 ft. and outbound platform by +3 ft. to hit the 225 ft. reference spec for 2-car 'stretched' trains. Extremely minor work, but that's the only subway station other than 15 ft. short Boylston that's not out-of-box compatible (if only by splitting-hairs margin) with the GLT fleet.
 
I was under the impression that the entire viaduct was in bad enough shape that you couldn't have two trains on it at once. (Though it certainly appears to be hugely overbuilt.) Do you know how much of the old steel section they're keeping as opposed to replacing with new viaduct?
 
I don't believe any of the steel viaduct will remain. New structure will start at the end of the stone viaduct.
 
I was under the impression that the entire viaduct was in bad enough shape that you couldn't have two trains on it at once. (Though it certainly appears to be hugely overbuilt.) Do you know how much of the old steel section they're keeping as opposed to replacing with new viaduct?

The viaduct is in pretty bad shape from what I've heard and I've also heard the one train at a time limit as well. The bid outlines $50m in work on the following:

Replacement of the track and bridge superstructure and safety walks; repair and rehabilitation of the concrete floorbeams, arches and piers; strengthening the arch spans with Carbon Fiber Reinforced Polymer (CFRP) fiber wrap; steel strengthening and repairs of the Bascule Span over the Charles River; Overhead Catenary System replacement; and signal replacement
 
And the bid says:
Work in general consist of repair and rehabilitation of the East Cambridge (Lechmere) Viaduct carrying the MBTA Green line from Science Park Station to Charlestown Avenue in Boston and Cambridge, MA. The viaduct includes 12 spans over Nashua Street, the Charles River, Museum Way and Charlestown Avenue.
The concrete part has 12 spans between Science Park Station and the Gilmore Bridge overpass (I didn't actually know that was called Charlestown Avenue). So this bid is pretty clearly only for the concrete part of the viaduct.
 
I don't think any sailboats with masts that large sail into the river. How high is the viaduct compared to the max clearance for the North Station draws (which raise angled), or the locks walkway? It may well be moot if the Green Line viaduct as as high or higher than limiters closer to the harbor.
George -- I believe that the rebuild of part of the viaduct when Science Park was renovated and / or the rebuild of the part of the viaduct when the North Station Green Line Superstation opened led to the permanent decommissioning of the Rail Draw at Science Park

However -- My guess is that it has not opened in at least a generation possibly going back to the days of when the Big Steam Locomotive was situated next to the Lock at the MOS
 
Why not Medford Hillside? "Medford" is too generic...

Sorry, George, but I disagree with you there. Most folks who are not super local don't know the relevance of "Hillside". If you want descriptiveness to the largest swath of riding public to avoid confusion and folks getting lost (local and tourist), the best name for that station is definitely "Medford/Tufts". I think they did a great job in naming the station for the widest understanding (unlike "Boston Landing"!).
 
College Ave station renamed to "Medford/Tufts"

And Tufts will pay the T $200k/year for the first decade of operations.

 
I think they could have called it "Tufts Medford" and we'd all have been a little better off. I get that both Tufts and Medford want the world to know that we are (just barely) cool enough kids to have a GLX stop.

It is the most "Medfordy" of the stops, but Ball Sq is about 40% Medford catchment. uHaul, when it happens is about 60% Medford (30% Somerville, 10% Arlington)

Medford/Tufts kind of implies that Ball (and future UHaul) are "not really Medford" which is misleading.
 
I think they could have called it "Tufts Medford" and we'd all have been a little better off. I get that both Tufts and Medford want the world to know that we are (just barely) cool enough kids to have a GLX stop.

It is the most "Medfordy" of the stops, but Ball Sq is about 40% Medford catchment. uHaul, when it happens is about 60% Medford (30% Somerville, 10% Arlington)

Medford/Tufts kind of implies that Ball (and future UHaul) are "not really Medford" which is misleading.
Tufts Medford is pretty close to Tufts Medical, which is how the latter appears on some maps.
 
Sorry, George, but I disagree with you there. Most folks who are not super local don't know the relevance of "Hillside". If you want descriptiveness to the largest swath of riding public to avoid confusion and folks getting lost (local and tourist), the best name for that station is definitely "Medford/Tufts". I think they did a great job in naming the station for the widest understanding (unlike "Boston Landing"!).

"Medford" is what you'd call a train stop in Medford Square. The center of the city. To call a train stop on the periphery of Medford "Medford" doesn't help with wayfinding. Either just call it "Tufts" or call it "Tufts/Medford Hillside". That's the neighborhood.
 

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