OvermodThere was some interest, probably a decade ago, in using nanodiamond lubricant in the bearing of at least one of these swing bridges. It was said to have greatly improved the bearing conditions; if true, that might be an option for seldom-opened bridges that could be 'moved down in priority'.
I have the impression that nanodiamond lubricants are used on sliding surfaces. And I think swing bridges would use roller bearings. So then that usage would be inappropriate.
I suspect an improvement would be better seals for those bearings, to keep "stuff" out. And, of course, proper maintenance.
Ed
blue streak 1 I can think of one swing completely rebuilt can you? I cannot. Which one?
I can think of one swing completely rebuilt can you? I cannot. Which one?
Clue : This swing bridge caused a major RR to put swing bridge out of service for 2 - 1/2 months to fix electrical problems among other items.
blue streak 1I can think of one swing completely rebuilt can you?
There was some interest, probably a decade ago, in using nanodiamond lubricant in the bearing of at least one of these swing bridges. It was said to have greatly improved the bearing conditions; if true, that might be an option for seldom-opened bridges that could be 'moved down in priority'.
As a matter of cost, I'd think that any new swing bridge, or a conversion from Bascule or lift to swing, would be a non-starter simply in terms of the environmental impact and the channel restriction. While I don't have direct costs, I'd suspect that a simple truss lift span and its towers and counterweighting would cost less and be far quicker to erect than a swing bridge, and I believe the rail transitions are more easily made 'movable' in a straight-lift design. Be interesting to see if there are modern framing-construction alternatives to a traditional bascule span design...
[quote user="blue streak 1"]
7j43k How many movable bridges have been built in the last 30-50 years, let alone swing? Probably not many railroad ones, as most of the rail routes were already built. Maybe road ones? /quote] I can think of one swing completely rebuilt can you?
How many movable bridges have been built in the last 30-50 years, let alone swing? Probably not many railroad ones, as most of the rail routes were already built. Maybe road ones?
/quote]
I can think of one swing completely rebuilt can you?
I cannot. Which one?
But my response was to your statement:
"Can anyone name say 10 swing bridges built as new in the last 30 - 50 years?"
The Brooklyn Bridge never was used by steel subway cars and never by steam locomotives in regular service. Occasionasl steam locomotives (small 0-4-4T Forneys) for positioning as Manhattan-end switchers and emergencies. The Bridge first had pure cable-car operation, then through elevated operation with the elevated cars (three maximum) hauled by the cable cars. Then trolley wire for illumination. Then start of elevated trains using electricity, third rail replacing trolley wire, streetcar tracks added in the roadway with trolley wire, end of cable operation in 1908. 1944: Elevated trains removed, streetcars moved from roadway to former elevated-train tracks. 1948: End of rail service across the Bridge.
[quote user="7j43k"]
Totally agree!
But that doesn't matter, as it's long past its 100 year useful life.
It's been repeatedly stressed by Amtrak that some of their bridges are OLD. As if that alone is a reason for replacement.
I am only supplying an example of an even older bridge that obviously must be torn down and replaced by some flat concrete spans with perhaps some decorative (styrofoam weight-saving) urns applied. Somewhere.
Also coming up for replacement is the suspension section of the Oakland-San Francisco Bay bridge. It's now 14 years shy of its 100 year useful life, and it's time to start thinking about the replacement. The cantilever span has already been replaced because the wood pilings supporting the piers were, well, wood. And thus clearly not adequate for today's world.
7j43kThe Brooklyn Bridge is pushing 140 years. Perhaps the replacement for this newbie should wait until after that one's been done.
The Brooklyn Bridge may carry subway cars, but it didn't get the pounding of heavy steam engines and freights like the Connecticut River bridge got over the years. Also the Brooklyn Bridge, being one of the first big suspension bridges, was overbuilt by modern standards. Plus it didn't have the movable wearing parts of a drawbridge.
blue streak 1 Swing bridges ae on the way out. Can anyone name say 10 swing bridges built as new in the last 30 - 50 years? Walk Bridge will more than double width with the new lift bridges. Now Conn river bridge is going to be a replacement Bascule bridge. North Portal is going to be a flyover. After reading the report of the Conn river shutdown luck was really with Amtrak. But I have to wonder the amount of overtime and extra payments to get the bridge back workiing. + Overtime for personnel that had to abandond other projects that had to be caught up. How many management, engineers, B&B, Electricians, track workers, bridge operators, and others to keep these releics operating for an ongoing standby. 4 shifts per week for how many persons?
Swing bridges ae on the way out. Can anyone name say 10 swing bridges built as new in the last 30 - 50 years? Walk Bridge will more than double width with the new lift bridges. Now Conn river bridge is going to be a replacement Bascule bridge. North Portal is going to be a flyover. After reading the report of the Conn river shutdown luck was really with Amtrak. But I have to wonder the amount of overtime and extra payments to get the bridge back workiing. + Overtime for personnel that had to abandond other projects that had to be caught up.
How many management, engineers, B&B, Electricians, track workers, bridge operators, and others to keep these releics operating for an ongoing standby. 4 shifts per week for how many persons?
Reading the article I cited, I got the impression that the cause was deferred maintenance and an unwillingness to improve existing equipment.
I suspect that maintenance and "minor" improvements come out of Amtrak's operating budget. Since Amtrak always loses money, there's no "profits" to re-invest.
But for all-out giant replacements, it's a capital investment, which just isn't viewed by many as a financial loss for Amtrak.
Though it's money that's spent, either way.
MidlandMike Near the bottom of page S-1 it states: The primary concern with the existing Connecticut River Bridge is its age, since it is nearing the end of its useful life. While they don't specifically mention salty spray off the Shoreline, salt will age the steel. In any case they can't repair something that is at the end of its useful life.
Near the bottom of page S-1 it states:
The primary concern with the existing Connecticut River Bridge is its age, since it is nearing the end of its useful life.
While they don't specifically mention salty spray off the Shoreline, salt will age the steel. In any case they can't repair something that is at the end of its useful life.
And then they list particulars, none of which is salt damage. It may be a problem, but curiously they neglected to mention it.
If you can find the inspection report from 2006, perhaps that will reveal more.
The PRR, NYNH&H, and even NYC all built draw spans that were not made to last as long as they have. A big problem is that many were center pivot type bridges that severely limits the amount of horizontal clearances from the bumpers. The coast guard appaarently apparently has guidelines that require more clearances for replacements. wide clearances were not neded for shipping when these bridges were built. + materials and designs at most were limited to span lengths. Do not build a bridge that cannot get standard parts 150 years from now.
EDIT: Predict that between now and end of 2023 there will be an ancient major movable bridge that will have an extended time being out of service. probably 1 or 2 minor route bridges.
Forgot did NJTT have a movable that "Sandy" put out of service for several months on the Jersy coast line?
7j43k MidlandMike Steel bridges over salt water don't last forever. I'm not seeing mention of a salt water problem in the following document, where they discuss on pages S-1 and S-2 reasons for replacement: https://railroads.dot.gov/sites/fra.dot.gov/files/fra_net/15548/May%202014%20Amtrak%20Conn%20River%20Environmental%20Assessment%20REDUCED.pdf Ed
MidlandMike Steel bridges over salt water don't last forever.
Steel bridges over salt water don't last forever.
I'm not seeing mention of a salt water problem in the following document, where they discuss on pages S-1 and S-2 reasons for replacement:
https://railroads.dot.gov/sites/fra.dot.gov/files/fra_net/15548/May%202014%20Amtrak%20Conn%20River%20Environmental%20Assessment%20REDUCED.pdf
ATLANTIC CENTRAL My point is most of the bridges on the Northeast Corridor date to the PRR and NH and could likely use some attention..... Sheldon
My point is most of the bridges on the Northeast Corridor date to the PRR and NH and could likely use some attention.....
Sheldon
Don't doubt it a bit.
But I get hesitant when it looks like Amtrak starts with "we need a new bridge 'cause the old one is old and yucky".
It's almost like they're not spending their own money.
If the old bridge is a pile of rust that's gonna kill people any day, make available the engineering studies that show that it CAN'T be economically fixed, but must be replaced. I DO know that there are times the old bridge is a lost cause. But show us. Assume we're not stupid. Please.
The Portal Bridge. The bridge has to open because tugs have to bring barges through. Nobody tried the idea of low profile tugs. Then the bridge doesn't have to open. Or maybe be replaced. But it's old. And yucky.
7j43k Ah, I see. I've stayed talking about the Connecticut River bridge, and you're talking about the Susquehanna River bridge. Ed
Ah, I see.
I've stayed talking about the Connecticut River bridge, and you're talking about the Susquehanna River bridge.
Read this:
https://havredegracemd.gov/susquehanna-river-rail-bridge-project/
7j43k Why do you think there will be TWO double track spans? It appears to me there would only be one. Ed
Why do you think there will be TWO double track spans?
It appears to me there would only be one.
The proposal shown to us here locally was for two spans. One would be built next to the existing span, were the pre 1906 span was, then after that is in service a second span would be build where the current span is.
Since they have a trackage rights arrangement with Norfork Southern, maybe they are rethinking the three track situation?
There is a wye on the north side of the river where most of the NS traffic comes down from Harrisburg.
It has been opened several times in the last 5 years or so. Both the quarry and a the fabricator in Port Deposit have had to move machinery and construction projects that once situated on a barge were taller than the clearance.
As for the rest of it, I'm not the one saying it needs to be replaced, AMTRAK is. I am puzzeled by the new plan for two double track spans when AMTRAK reduced the number of tracks from here to Baltimore from 4 down to 3 some time ago?
Seems to me they could just fix it.
As for old bridges still in service, this one not far from here has most of them beat:
https://en.wikipedia.org/wiki/Thomas_Viaduct
ATLANTIC CENTRAL We are still waiting here to be told when they might replace the Susquehanna River AMTRAK bridge, a swing span built in 1906. A proposed set of replacements that would provide 4 tracks on two spans has been shown to the City of Havre de Grace and the state. The swing span is only opened fot occasional industrial traffic up stream at a quarry and a fabricator in Port Deposit. The rails are bolted or welded and 24 hour notice is required to open the span.
We are still waiting here to be told when they might replace the Susquehanna River AMTRAK bridge, a swing span built in 1906. A proposed set of replacements that would provide 4 tracks on two spans has been shown to the City of Havre de Grace and the state.
The swing span is only opened fot occasional industrial traffic up stream at a quarry and a fabricator in Port Deposit.
The rails are bolted or welded and 24 hour notice is required to open the span.
With a 52' clearance, I question whether this bridge actually HAS to be opened ever again.
All thru downtown Havre de Grace you can here the pin connected Howe deck steel truss spans rattle as the Acela and MARC trains fly across it at 88 mph......
Maybe try some oversize pins. They're not hard to make.
Looks like it will reach its 120th birthday before they replace it. https://en.wikipedia.org/wiki/Amtrak_Susquehanna_River_Bridge My grand children live 100' from the south approach which passed thru/over the north end of downtown Havre de Grace. A major derailment would be very bad..... Sheldon
Looks like it will reach its 120th birthday before they replace it.
https://en.wikipedia.org/wiki/Amtrak_Susquehanna_River_Bridge
My grand children live 100' from the south approach which passed thru/over the north end of downtown Havre de Grace. A major derailment would be very bad.....
The Brooklyn Bridge is pushing 140 years. Perhaps the replacement for this newbie should wait until after that one's been done.
Here is a fascinating read about problems with the existing bridge:
https://heavymovablestructures.org/wp-content/uploads/2017/12/00913.pdf
It doesn't look like the bridge being old meant that it was irrepairable. Note mention of repairs over time.
Considering the age of the bridge and the Scherzer rolling lift design, replacement parts may well be unavailable or have to be custom-made (expensive).
blue streak 1 No indication of what kind of movable bridge is contemplated. The present very long bascule bridge appears somewhat difficult to get it to stay in alignment. Is a lift bridge cotemplated?
No indication of what kind of movable bridge is contemplated. The present very long bascule bridge appears somewhat difficult to get it to stay in alignment. Is a lift bridge cotemplated?
from
https://www.amtrak.com/connecticut-river-bridge
It will be a trunnion Bascule (as opposed to rolling). It and the approach spans will be built 52' away from the old one.
It says that the old rail miter joints limit train speed to 45 MPH. The new ones will have a speed limit of 70 MPH.
I do wonder why they couldn't put the new miter rail joints on the old bridge.
It also says the existing one fails to open and close properly. Again, I wonder why they couldn't fix/repair that.
Remember the running Amtrak excuse now that it has all the funding it could possibly want. It's not "were ready to execute" instead it's "we are too short of people". They pushed back the second Chicago to Twin Cities train to late 2024, that is a tentative date even. They had full funding on that project for a year now and they will not even start construction until 2023.
as slow as molassas. Announcement appears to be somewgat premature. Just going to start procurement phase in early 2023. What the heck has Amrak been doing up to this time? This is for a design - bid - build contract.
Amtrak begins procurement for construction of new Connecticut River bridgeAmtrak begins procurement for construction of new Connecticut River bridge - Railway Track and Structures (rtands.com)
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