Walking the bridge...

errlloyd

I was thinking about the Malahide viaduct problem while looking at some of the pictures, and I realised the bridge itself is still very stable. The span thats missing is bridgeable for pedestrian traffic.

This led me to wonder why we don't just run trains up to either side, have the passengers disembark, walk the bridge and board another synchronised train at the other end. The disruption would be a disturbance to passengers, and its possible the trains would have to travel slowly up to the bridges to avoid over running, however it would still be significantly better than busses.

And even if the bridge was unstable, floating pontoon could be easily moved into the lagoon / lake / estuary area to provide a pedestrian crossing.

(I guess the reason I am posting this is to get some opinions, I think it would be simple enough)

Actually just measured, its 1.2 km.. 15 minute walk is maybe too long to make this idea workable. Trains probably can't venture onto the bridge.

fh041205

I'm going to say to you now, exactly what everyone else will say to you here. That idea is utterly utterly ridiculous. There are so many things wrong with it that I can't even begin to list them. If you worked for me and suggested that as a solution I would hit you with the nearest blunt object and then sack you. I'm very very glad that you aren't (i presume/pray) involved with IR.

If this isn't a wind up I'll eat my hat, but until then tally ho.

errlloyd

Hmm I really don't get the issue with stopping a train and walking. Sure the same thing happens every day in Paris with people walking from Gare L'est to Nord. I'm not a train driver, don't know how long it takes to stop, how much a risk it is to stop near the end, however I have never seen a train hit a buffer at the end of the line, I'm not an engineer, I don't know how ****ed that bridge is, I'm not a manufacturer of floating pier, dunno how hard it would be to implement, however methinks it would be easy enough, the stuff is used temporarily at sailing weeks like the DL Regatta.

But I am a commuter, I wouldn't mind walking to save myself a bus journey :P

P_1

Good idea in theory, however do bear in mind that the viaduct is in an extremely exposed area. The thoughts of a having to walk over a set of drooping rail lines with a torrent rushing underneath on a dark and wet octobers morning simply gives me the willies.

errlloyd

Hmm I would say they can probably pimp the place out with some handrails and a foot bridge built on the current viaduct bridging the missing section in less than a week, a lot less than 3 months anyway.

However I have said before, not an engineer, just bored.

Wishbone Ash

errlloyd wrote: »

However I have said before, not an engineer

......nor likely ever to be one!

errlloyd

No probably not, not really into the whole 36 hours of lectures per week shiz. However there really shouldn't be an engineering issue at all. If you wanna point it out feel free.

70 years ago the allies were able to bridge the Rhine with suitable bridge to drive tanks over in a day. Were there is a will?

fh041205

Part of the bridge failed and collapsed into the sea. Thats a pretty big engineering issue to even the most passive of aspiring engineers such as myself.

The phrase 'fool me once' springs instantly to mind.

errlloyd

Orly? And thats no an issue for the multiple workmen on the bridge at all. Are you familiar with the structure, have you ever sailed, walked or kayaked near it? My gut instincts tell me 90% of that bridge is still fine.

Ok, so when the structural engineers say its unsafe we can resort to the above stated plan B, which was the floating bridge. The beauty of which is, it cannot collapse.

I don't care if everyone on this board except me has a master in Mechanical, Structural and Civil Engineering. Getting pedestrians from one side to another is very possible (not easy, maybe not economical, but undeniably possible in a decent time).

The only real problem is making the whole thing legally "safe". Because obviously if its not it can never happen. Nanny state. Get off train, 5 minute stroll across bridge, re-board train, where is the issue?

admiralofthefleet

have a look at this video, would you seriously expect people to walk over that

https://www.youtube.com/watch?v=c-iV2nDopvY

errlloyd

admiralofthefleet wrote: »

have a look at this video, would you seriously expect people to walk over that

Hmm I think you misunderstood the suggestion. The suggestion is that a small lightweight pedestrian bridge is built over the collapsed section, or floated alongside the collapsed section.

As for walking on the rest of the bridge, the lad who took the video didn't seem to have much an issue.

Hmm I think I need to clarify. I don't think an idea like this would ever happen in a western country these days. I'm not some 80 year old longing for the old days, I just think we are too willing to see flaws in an idea, its easier to just throw a load of buses on a route and get up 45 minutes earlier each morning.

Its very difficult to build a railway bridge quickly so its out for a while. Its piss to build pedestrian bridges though, why the hell can't people just switch trains.

P_1

Ok I think I can see where the OP is coming from now. Tbh it does seem possible.

What probably needs to be done:

-Put in a crossover near Donabate
-Put in a temporary buffer on the south bound track halfway down the causway over the estuary
-Build a temporary platform over the north bound track
-Put in a pontoon on the western side of the bridge (perhaps that can be enclosed, thus protecting passengers from the elements)
-Put in another temporary buffer and platform at the Malahide end of the estuary.

Although if the busses can keep up their current performance using the M1 and Port Tunnel why bother.

ronano

fh041205 wrote: »

I'm going to say to you now, exactly what everyone else will say to you here. That idea is utterly utterly ridiculous. There are so many things wrong with it that I can't even begin to list them. If you worked for me and suggested that as a solution I would hit you with the nearest blunt object and then sack you. I'm very very glad that you aren't (i presume/pray) involved with IR.

If this isn't a wind up I'll eat my hat, but until then tally ho.

i laughed so hard

errlloyd

I was under the impression the buses were doing a very poor job, if they aren't why bother indeed.

There is actually no reason why it can't be done, just a few why it wouldn't be done.

P_1

errlloyd wrote: »

I was under the impression the buses were doing a very poor job, if they aren't why bother indeed.

There is actually no reason why it can't be done, just a few why it wouldn't be done.

Well i suppose that depends on where you're travelling from OP?

My journey time is much quicker with the busses using the tunnel.

errlloyd

Don't live en route, used to.

skelliser

i dont mean to be rude or insulting but are you slightly retarded?

loyatemu

skelliser wrote: »

i dont mean to be rude or insulting...

well you've failed there - how much more insulting could you be.


The original suggestion is fairly outlandish - I can see where you're coming from OP but its not a workable solution. You'd have to build new platforms, put a pedestrian deck with handrails and lighting on the bridge as well as spanning the missing section, and it would still be a long and very exposed walk. Plus it would interfere with the work to restore the rail line.

Morpheus

you cannot put buffers halfway down the causeway - at the minute the entire causeway is considered no go until a proper structural survey, including seabed, is completed along its ENTIRE length, who's to say another span wont fail in the next couple of weeks? They didnt see this one coming so its just silly to suggest this.

Secondly, seriously? The allies were in a war zone, this was a temporary bridge built without due consideration for 100% safety of the individuals using it. the idea was to rush across as quickly as possible while it still hadnt been bombed, shelled, blown up.

Now as for the floating pier idea - you mean like mulberry harbours used in the DDay landings!!??? This wont happen, the estuary rises and falls, ebs and flows with the tides, it would take just as long to figure out the logistics of a large floating pontoon as it will to replace the existing bridge.

any "walkaround" or bypass method will also suffer the tides, which will cause access issues, you cant simply build a stairs which grows and shrinks, down onto it on each side, so unless it is attached to the existing causeway which as in point one above is still considered entirely unstable along its length.

The most viable - and sensible - solution in my opinion is a ferry across the estuary, if I had a boat id do it myself, the only logisitical problems being where to land the ferry on each side and how long would the journey take compared with buses.

cargo

I think errlloyd is on commission from the engineering company who designed this for Dubai...

Thousands of cars drive across this every day.

Just build it a couple of times longer and equip all the trains with longer travel suspension on the wheel carriages and there you go... simpels


http://en.wikipedia.org/wiki/Floating_Bridge,_Dubai

Floating Bridge (Arabic: الجسر العائم‎) is a pontoon bridge (floating bridge) in Dubai, United Arab Emirates. It connects Riyadh Road, Dubai Courts and Creek Park on the Bur Dubai side with Baniyas Road, Deira City Centre and the Dubai Creek Golf & Yacht Club on the Deira side. Floating Bridge is the fifth crossing on Dubai Creek.

The Floating Bridge came to reality due to the vision of Sheikh Mohammed bin Rashid Al Maktoum and the expertise of the Dubai Roads and Transport Authority (RTA). Its uniqueness comes from floating structures specialist Clement Systems Gulf. Clement Systems Gulf's patented technology allowed for more than 19,000 tons of cement, reinforced with over 1,500 tons of steel to float across the 300 metre (985 ft) wide Dubai Creek.

The 300 metre (985 ft) long bridge - 3.3 metres (11 ft) in height - floats on a harsh saltwater Creek environment which required special construction materials. It was also constructed to withstand wind speeds of up to 160 kilometers (100 miles) per hour and waves of up to 1.8 meters (6 ft) in height. Moreover the structure dynamically distributes energy from waves and pressure from vehicles across the length and breadth of the platform in such a way that they cancel each other out.

Picture of level of flex here.

http://qualityjunkyard.com/wp-content/uploads/2009/02/floating-bridge-in-dubai-2.jpg

BrianD

You're also forgetting that that section of bridge is about to become a building site very shortly (we hope) and not a place for hundreds of passengers to be walking through.

errlloyd

@ Morpheus and Cargo.

What I meant is actually the stuff we build modern Marinas out of. There is a km of the stuff around the corner from the bridge at the Malahide Marina.

Tbh the same things could be used to equip your ferry, I had thought about the ferry, but hesitated because I can't see a ferry being big enough to transport a train load of people, and still be maneuverable in the estuary.

I think the best way to explain the idea, is use an obviously (and frequently) workable example.

The DART bridge over the liffey breaks. John Smith needs to get home from Bray to Clontarf, so what does he do? He gets a DART to Tara street, he gets off the dart, walks across Butt bridge and gets back on another DART from Connolly.

This is the same, except instead of Connolly and Tara we have two temporary stations, and instead of Butt bridge we have some sort of temporary foot bridge.

Ps: Never seen that floating bridge before, but tbh it looks ****ing epic.

BrianD

errlloyd wrote: »

@ Morpheus and Cargo.

What I meant is actually the stuff we build modern Marinas out of. There is a km of the stuff around the corner from the bridge at the Malahide Marina.

Tbh the same things could be used to equip your ferry, I had thought about the ferry, but hesitated because I can't see a ferry being big enough to transport a train load of people, and still be maneuverable in the estuary.

I think the best way to explain the idea, is use an obviously (and frequently) workable example.

The DART bridge over the liffey breaks. John Smith needs to get home from Bray to Clontarf, so what does he do? He gets a DART to Tara street, he gets off the dart, walks across Butt bridge and gets back on another DART from Connolly.


This is the same, except instead of Connolly and Tara we have two temporary stations, and instead of Butt bridge we have some sort of temporary foot bridge.

Ps: Never seen that floating bridge before, but tbh it looks ****ing epic.

Except it's not remotely the same. There's a public street between the two stations. It would be the same if you suggested walking around the estuary to Malahide and then on a train again.

Carawaystick

BrianD wrote: »

Except it's not remotely the same. There's a public street between the two stations. It would be the same if you suggested walking around the estuary to Malahide and then on a train again.

Fingal Co.Co. have it as a stated objective to build a pedestrian link from Malahide to Donabate. Check the Co.Co Minutes.

If there was a ped link across the estuary, then the question would be there isn't there a train service to Donabate,

There is plenty room on the causeway, and there's no engineering reason why the causeway should fail. Building a ped bridge over the gap should be a simple problem for the engineers.

Morpheus is not completely correct to compare the causeway which didn't fail to the bridge which did. Morpheus is probably correct to say you can't have platforms for passengers to disembark on the causeway itself.
Morpheus is wrong to say you can't have floating ramps and walkways. These are on almost every marina in the land. Tides come in and out, the main marina walkway floats and the ramp down from the solid land rolls along to the main walkway.
Also there is much less tidal variation on the inner estuary in Malahide, wrt the Irish Sea.

errloyd is probably correct in questioning why there is no plan to get rail services working to Donabate asap.

Bluetonic

Carawaystick wrote: »

errloyd is probably correct in questioning why there is no plan to get rail services working to Donabate asap.

There are trains running from Dundalk/Drogheda to Donabate for the last few days.

Run_to_da_hills

BrianD wrote: »

You're also forgetting that that section of bridge is about to become a building site very shortly (we hope) and not a place for hundreds of passengers to be walking through.

No problem, just make sure they wear hard hats, high vis vests and protective boots.

BrianD

Carawaystick wrote: »

Fingal Co.Co. have it as a stated objective to build a pedestrian link from Malahide to Donabate. Check the Co.Co Minutes.

If there was a ped link across the estuary, then the question would be there isn't there a train service to Donabate,

There is plenty room on the causeway, and there's no engineering reason why the causeway should fail. Building a ped bridge over the gap should be a simple problem for the engineers.

Morpheus is not completely correct to compare the causeway which didn't fail to the bridge which did. Morpheus is probably correct to say you can't have platforms for passengers to disembark on the causeway itself.
Morpheus is wrong to say you can't have floating ramps and walkways. These are on almost every marina in the land. Tides come in and out, the main marina walkway floats and the ramp down from the solid land rolls along to the main walkway.
Also there is much less tidal variation on the inner estuary in Malahide, wrt the Irish Sea.

errloyd is probably correct in questioning why there is no plan to get rail services working to Donabate asap.

It would be great if there was a ped link but there isn't and if one can be built as part of the viaduct rebuild then put it in!

But at the moment there is no proper access to the viaduct and on the viaduct for pedestriansso the OP's plan is a non-runner. Plus it's about tobecome a very confined building site. Why even suggest this when the most practical solution is bus transfers?

Also, there is no similarity between the city centre example given unless you take the circuitous route I suggested.

Carawaystick

Bluetonic wrote: »

There are trains running from Dundalk/Drogheda to Donabate for the last few days.

None today and None tomorrow though.