Infamous 'can opener' bridge in Durham, NC, is finally being 'fixed'... 4

[LittleInch]

I think 500 tons is way off though. The previous estimate was about 20 which seems low, but there isn't that much to that bridge. It's only 25m of single track railway supported by a few C section beams. If it was total of 100 tons I would be surprised.

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[Alistair_Heaton]

I was going off one that was removed north of Aberdeen on the Peterhead road. It was less width and 250 tons.

I also have zero clue what the APN of USA roads is, Or if the pavements are the same.

Getting the load pressure down to the legal max of a road vehicle seems sensible to me. Especially when all it requires is the temporary laying down of some plate. Which is pretty standard for mobile cranes. And even then they sometimes kill the surface.

 

[3DDave]

That pressure is way under what a woman's high heel puts down. Maybe keep them off the apron as well?

I did look for ways that I missed major contributors to weight, but it's clearly pairs of c-channels, one under each rail and rail companies seem unlikely to overspend. A current heavy locomotive, which should weigh a good deal more than any rail car so it should be the upper limit, is about 400 kips. It's weight is split to at least 2 trucks, so the concentrated load is just 200kips and the beam is not a single free span.

No links to that narrower, heavier bridge? This bridge's superstructure isn't as wide as the ties; getting narrower is footpath territory.

Yes - mobile cranes can do damage. Because the heavy ones put down more load than a locomotive. But this isn't a mobile crane or the higher loads that other mobile machinery can put down.


Edit - The 20 kips is per beam. The bridge has 2 beams, so twice that amount for the entire bridge. Of course it is then divided among twice the number of jacks and scaffolds, so back to the original loading.

 

[charliealphabravo]

Ahhh too bad about the ads in the video. I use the AdBlocker extension for Chrome and didn't see them. It works almost all the time.

Edit: This video screenshot shows them working at the train station which is about 600 feet way. I suppose there wasn't much they could do about the grade without it becoming a bigger project. Also I sounds like the job was supposed to be finished in less than a day so the train schedule would not be interrupted.

 

[Alistair_Heaton]

High heels do destroy the apron, also air bridges as well and aircraft internal flooring and steps.

Thankfully the amount of pax these days that travel in the high pressure type heels is extremely small and gets smaller by the year. This is pushed by security issues getting through metal detectors with steel shanks in them more than anything else.

Btw the aircraft most likely to sink on aprons and taxi ways at the biz jets with their skinny tyres. The big heavies eg 747 have a collosal tyre foot print and require relatively low APN values.

 

[dgallup]

Those spike heels should be considered a lethal weapon by TSA anyways.

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[Alistair_Heaton]

Btw the bridge I was on about could take the Flying Scotsman going over it.

I would still stick spreader plates under the feet. It's not as if it costs anything A rail yard is bound to have some plate kicking about.


I would also put a wire into the stone and attach it to the top. So the frame couldn't go sideways.

Mind you I am a coward when it comes to these things In the house I am building I have 2 eye bolts 4 meters up on the cable ends to strap scaffolding onto. At least you can put some lateral force into jobs and not be scared it's going toppel away with a lardy arse like me 8 meters up trying to put a 30mm hole through 450mm of solid wood.

 

[3DDave]

Destroy? Like punch through? British birds are built bigger than I suspected.

The Flying Scotsman was a passenger train, not a locomotive. But maybe the weight is related to the birds? The first run of that line might have been over cast iron bridges, known for their problems with "crystalizing" until the concept of fatigue failure in metals was better understood. The typical response was to just make the structures absurdly heavy. Or was this a stone arch bridge?

 

[LittleInch]

It's an engine.

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[3DDave]

"The Flying Scotsman was a named passenger train service from London Paddington to Exeter St Davids. It ran from 1849 until 1892, originally over the Great Western Railway (GWR) and then the Bristol and Exeter Railway."

I see that they named an engine for that line.

From the fan page: "By 1924, when it was selected to appear at the British Empire Exhibition in London, the loco had been renumbered 4472 – and been given the name ‘Flying Scotsman’ after the London to Edinburgh rail service which started daily at 10am in 1862."

So while there is support for each side, the service had the name for 62 previous years, the locomotive isn't all that heavy and doesn't apply a near point load. If it takes a massive bridge to hold it, that's a commentary on low strength bridge building materials rather than the size of the engine.

It's quite small. At just over 30,000 lbf tractive effort; is dwarfed by the UP Big Boy series at 135,000 pounds of which 25 were produced, built just 17 years later.

 

[Alistair_Heaton]

The bridge was on the Formartine and Buchan Railway which opened in 1865. And was closed to pax with the Beeching cuts in 1960's freight continued on it until the 70's. The metal track was lifted


You can still walk along it and this site has a picture of a typical bridges which were on it that's a single lane one the one removed was about 2.5 times that span. The pic of the bridge I was referring to is not on it. It was speared by a crane with the gib "accidently " left up. Lorrys going up to the Peterhead port with oil equipment had to take a 25 mile detour to get round it. So some 30 odd years ago now an about to retire crane driver hit it doing about 45 mph with 40 tons of crane which shoved it off to the side. And within an hour various oil company's had arranged it to be removed to safety at the side of the road where is sat for years. Every attempt to get it put back on was met with sorry we can't lift it (it was a historically protected bridge so in theory they were meant to put it back the way it was). The old crane driver had his license revoked (he had 3 days left anyway) the 1000 UKP fine was paid by the road hauliers in Aberdeen and he got some 50k UKP retirement present plus 500 quid and a card from Aberdeen police who were as fed up with it as everyone else. . Which some reckon was about 6 months worth of savings of the route now not having a height restriction. I can remember driving under it as a kid and seeing it next to the road. I only got told the story when I was driving the artics in Aberdeen as a holiday job at Uni in my 20's. I don't know for sure if its true but it has a ring to it that it might be mostly true, its definitely something the oil company's would do in that period. The fuel saving wouldn't have been the priority. The cutting the transport time to get a part offshore would have driven it.

https://www.walkhighlands.co.uk/aberdeenshire/formartine-buchan-way.shtml

The flying scotsman is built for speed. And you can still travel on it. I was very lucky to have had a cab on it.

With a huge amount of effort it can still beat the modern train on the route. The huge effort is the provision of water and coal when required which is extremely often on a speed run. But she is a beauty when going flat out.

 

[3DDave]

The new beam took a bite.

https://www.youtube.com/watch?v=-VokezIMLKE

Is it just 3 weeks? Happy Thanksgiving!

 

[LittleInch]

Nah, that was a nibble....

Previously it would have rolled the roof back.

Are those trucks commonplace / a standard design?

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[IRstuff]

Wonder if the rental company pays attention to these videos?

TTFN (ta ta for now)
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