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Discussion relating to the operations of MTA MetroNorth Railroad including west of Hudson operations and discussion of CtDOT sponsored rail operations such as Shore Line East and the Springfield to New Haven Hartford Line

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 #1347182  by csor2010
 
Ridgefielder wrote:
F-line to Dudley via Park wrote:Same, because the approaches are unmodifiable with the surrounding density. The swing just means it can go up and down much faster. Since barge traffic is virtually the only maritime traffic left there the swings wouldn't have to go anywhere near max height to slip the barges under. That ends up shaving more time still off the clock of a start-to-finish bridge opening.
Actually- not to start an argument but I think they could increase the clearance. The current swing span is a deck truss. If the replacement- lift, bascule or whatever- is a through-truss or a through-girder, there should be a decent increase in clearance above mean-high-water.
Agreed; even a deck-girder replacement of the approach spans will result in increased clearance outside the movable span. And all of the renders I've seen show a through-truss lift. The bridge as it stands is pretty much a worst-case for clearances in the closed position.
 #1347219  by 35dtmrs92
 
I have been thinking the same thing; pretty much anything is better than the current deck truss in regard to closed-position clearances. Even better, with a lift bridge, there will be no need for the center swing span pier, meaning a wider channel, meaning more facile, quicker barge movements. IMO, geometric changes to the rail alignment aren't going to yield much anyway since most MN mainline trains seem to stop at South Norwalk anyway. Out of curiosity, are the renderings of the bridge publicly available yet?
 #1347240  by DutchRailnut
 
a lift bridge can be constructed with current bridge in place, any of other designs can not.
the lift towers can be constructed next to existing tracks and the lift spans hung over bridge , once everything is in place you float old bridge out on barges.
total interruption of service would be probably one or two weekends.
 #1351469  by Jeff Smith
 
Brief, fair-use quote from above link per site policy:
State ‘30 percent’ there on Walk Bridge design

NORWALK, Conn. – A temporary railroad bridge would be built alongside the aged railroad bridge over the Norwalk River as part of the herculean task of replacing the problematic structure, according to a plan devised by the Connecticut Department of Transportation (ConnDOT).
...
The idea of a movable bridge that goes straight up has been discarded, they say. It’s down to two concepts:

•A bascule bridge that features one piece that hinges on one side
•A bascule bridge that splits in the middle, with split tracks on either side; that would mean that the tracks would go up and down independently

ConnDOT plans to divert railroad traffic north of the bridge by creating a bypass, starting “somewhere around Fort Point Street,” John Pinto said. That will lead to a temporary bridge, with two tracks, alongside the current bridge.
...
There also will be a switch on the Norden Place property owned by Metro North, he said. “If a train is coming down Track 4 they will be able to very conveniently switch them onto Track 1,” Pinto said.
...
“What they’re going to do is, as a regular tug and barge will bring it up (to one side), then they’re going to push it though and have a tug waiting on the other side. It’s a handoff,” Pinto said. “They’ve done it before.”

So if you can handle Norwalk River marine traffic without having a movable bridge, why is the state planning to spend $400 to $500 million to build a bascule bridge?
...
 #1351472  by Ridgefielder
 
How the heck are they going to build a temporary bridge upstream of the existing one? They'd have to demolish a big chunk of the Maritime Aquarium for the approach span- there can't be more than 15' between the building and bridge. And why has a lift span been ruled out-- do Malloy's busway buddies also own a bascule manufacturer?

If the USCG won't allow the Harlem River lift bridge-- which must see 500+ rail movements a day and is opened maybe 5x/year for actual river traffic-- to be converted to a fixed span, there is absolutely no way they'd allow the Norwalk River bridge to become a fixed span.
 #1351594  by NH2060
 
Looks like this will be a repeat of when PECK was replaced in the 1990s. If you recall there was a temporary span constructed next to the old drawbridge while the new one was built (though there was ample room for one). The draw span itself could very well end up being exactly the same as PECK or perhaps Niantic. It allows for higher clearances over the current span and a Cos Cob-style deck girder.

Now with the design of the bridge 30% complete and a bascule already preferred over a lift span who knows what will happen with the remaining 70%. But it sounds like the only way to

Here's an article from Sept. 22 on the property acquisitions for the project:
The Connecticut Department of Transportation (ConnDOT) is looking to acquire 17 properties -- some permanently, others for use as temporary easements -- as part of replacement of the Walk Bridge.

The ConnDOT acquisition process includes, among other steps, a property title search and impact valuation followed by negotiations with the property owner. If an agreement isn't reached through negotiation, the matter moves to eminent domain and condemnation.

http://www.thehour.com/news/norwalk/pro ... 0618b.html" onclick="window.open(this.href);return false;
 #1351618  by Arlington
 
^ 17 parcels? any chance for that kind of outlay they would end up with clearance for faster running (better track spacing for a train tilt/clearance) or a 5th track?
 #1351625  by DutchRailnut
 
the cost of adding a 5th track would be astronomical not only walk but each and every overpass/underpass and catenary structure.
higher speed ?? no overall speed will remain at 70 plus or minus, the bridge speed might be raised from 40 but even that is doubtful.
 #1351639  by DutchRailnut
 
The approach to tunnel would require a start of grade at westport at one end and before Rowayton as it still needs to accommodate freight.
The tunnel would require the stations of Rowayton , South Norwalk and East Norwalk to be build in the tunnel.
a dream project like that would cost equivalent of Amtrak Gateway project.

plus above ground station and right of way would need to be maintained for access to Danbury Branch.
Last edited by DutchRailnut on Tue Oct 06, 2015 9:00 am, edited 1 time in total.
 #1351640  by Jeff Smith
 
If they were going to clear anything up with a 5th track, they should look at acquiring the building on North Main right at the mouth of the Danbury Branch. From a satellite view that appears to be the only north-side impediment to a New Canaan branch style track 5 setup similar to Stamford. It could still be a stub track; you'd have to tear down the inbound station and parking deck to make it through, but it still keeps from fouling the main for a shuttle train.
 #1351641  by DutchRailnut
 
I don't think he ment it as a track for Danbury, plus most shuttles now continuou to and from Stamford so they still need to use other tracks.
 #1351660  by Ridgefielder
 
Jeff Smith wrote:If they were going to clear anything up with a 5th track, they should look at acquiring the building on North Main right at the mouth of the Danbury Branch. From a satellite view that appears to be the only north-side impediment to a New Canaan branch style track 5 setup similar to Stamford. It could still be a stub track; you'd have to tear down the inbound station and parking deck to make it through, but it still keeps from fouling the main for a shuttle train.
I don't think fouling the main for the Danbury shuttle is really that much of a problem. It's only on there for what, 200 yards from the junction to the switch for the WB pocket? That's certainly not enough of a problem to require the outlay of tens of millions of $$ you'd need to acquire the properties on North Main and reconfigure the rather tricky bridge across the intersection of Main and Washington streets.

Guess my bigger question is- why did they rule out a lift span? Is the bedrock unsuitable for the needed tower footings? Acquiring property and building a temporary bridge doesn't exactly sound like the cheap alternative.

Also- the blog post from Nancy on Norwalk says the temporary bridge would be north of the current structure, but the properties cited in the Hour article as being potential CDOT acquisitions are on the south side of the tracks. And they're all on the east bank of the river-- but I don't see how it would be possible, without an extremely tight radius curve, to get the line onto a temporary structure without demolishing either the IMAX theater or part of the Aquarium on the west bank.

If anything, by the way, I could see this being a spur for the State or somebody to throw enough money at the HRRC/Maybrook problem to make it go away and get the P&W trains to Danbury back onto a Devon-Derby Jct. routing.
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