Black Bridge, Nuneham: southern abutment failure

[whole diary]

[Mark A]

The large pipe that looks to be 12-18" in diameter, mounted on the exterior upstream side of Nuneham Bridge. Anyone know what it carries? (Or carried, perhaps...)

Mark

[Mark A]

Looking at images of the bowstring spans at Nuneham, three things:

* No windbraces. (Many many bowstring bridges have these, tying the tops of the arches to each other)

* It's not immediately obvious, for the steel spans, as to how Nuneham's bridge bearings are handled. The image below is one of the roller bearings carrying the 1930s replacement bridges across the Avon on the Midland line at Kelston. Hopefully Nuneham has something that can handle rotation, as there's a bit of that going on.

* The steel spans themselves are in a state of neglect, with instances of full-depth corrosion on parts of the structure.

Mark

[stuving]

The large pipe that looks to be 12-18" in diameter, mounted on the exterior upstream side of Nuneham Bridge. Anyone know what it carries? (Or carried, perhaps...)

Mark

The obvious answer is water - isn't that sort of pipe usually a water main? Since the Appleford bridge has no such hanger-on, I guess it supplied the Culham loop from Abingdon.

It looks serviceable, but may not be needed - I expect the exotic machinery near Culham needs and has a big new pipe. This one might still supply the village, perhaps. I'm not aware of any accessible map of water mains, unless you've bought a house nearby or it was included in a planning application (in which case you are not allowed to look at it when you've found it).

[ellendune]

Most likely water, but could be gas. 

[Mark A]

On railforums this morning, there's quite the telephoto image. A thumbnail available and a somewhat larger version if logged in to the forum demonstrating why the bridge was starting to be referred to as a 'Ski jump'.

Also, some hints on Twitter that crossing this, from the perspective of someone driving trains, was a singular experience and even more singular should the arrival of a passenger train coincided with a freight train on the other line.

https://www.railforums.co.uk/threads/nuneham-viaduct-shut-didcot-oxford.246310/page-9#post-6156274

Mark

[IndustryInsider]

On railforums this morning, there's quite the telephoto image. A thumbnail available and a somewhat larger version if logged in to the forum demonstrating why the bridge was starting to be referred to as a 'Ski jump'.

Also, some hints on Twitter that crossing this, from the perspective of someone driving trains, was a singular experience and even more singular should the arrival of a passenger train coincided with a freight train on the other line.

The telephoto image foreshortens things (as you might expect!) and makes it look far more dramatic than it was.  As someone who did drive a train over it I can confirm it was just fine from a ride quality perspective at 5mph - I've certainly driven over far worse track than that in remote sidings.  It is quite a dip though and was packed with ballast on more than one occasion over the months as it slowly sank.

That's not to say it would have been any fun at much more than 5mph (or much more than 20mph when that was the speed restriction).  Having seen some photographs of the sides and underneath I can say that I am very much relieved it has now been closed, even if much of the damage wasn't structural!  Sadly I can't share those photos as they are marked 'Internal use only', so you'll have to take my word for it.

[bobm]

Having seen some photographs of the sides and underneath I can say that I am very much relieved it has now been closed, even if much of the damage wasn't structural!  Sadly I can't share those photos as they are marked 'Internal use only', so you'll have to take my word for it.

Thank you for giving us the “gist” of them.  Helps the overall understanding.

[Worcester_Passenger]

We've been travelling (by train) around Slovenia, Austria (for work) and Hungary (for pleasure) for the past two weeks. 

We left Budapest at 09:40 on Tuesday (April 4) and stayed overnight in Wuerzburg (we don't like travelling on sleepers or in the dark). 10:24 from there on Wednesday morning, expecting to get to St Pancras on the Eurostar at 20:00 and catch the 20:50 out of Paddington back to Worcester.

On the ICE from Cologne to Brussels, I power up the laptop and come here, only to find the bad news about The Bridge.

So, a taxi to Marylebone instead of Paddington.  Where we find that Chiltern aren't running north of Banbury, that only one out of four ATMs^‡(resolve) are working and that M&S can only offer Gin and Diet Tonic. Has the country started falling apart since we went away?

We catch the 20:40 from Marylebone to Oxford, a 4-car unit which is the most crowded train we've been on in two weeks. About the same level of standing as trams 4 and 6 in Budapest.

At Oxford (arrive 21:48) we cross the bridge to platform 4, where GWR^▸ (Great Western Railway) are very sensibly holding the 21:42 departure to Great Malvern (which would have been our 20:50 from Paddington). Thank you! OK, we have to wait for the single line at Evesham, but we still get home.

[CyclingSid]

Update from Paul Clifton https://twitter.com/PaulCliftonBBC/status/1643986645233074176?cxt=HHwWgIDUyZjJztAtAAAA

[bobm]

I have seen reports of the closure remaining until 9th June.  Then re-opening with a temporary speed restriction for another week after that.

[grahame]

Update from Paul Clifton https://twitter.com/PaulCliftonBBC/status/1643986645233074176?cxt=HHwWgIDUyZjJztAtAAAA

Summary from that feed ... until early June for a tempoary fix, then something more permanent; around half the freight trains are running, diverted via Acton.    

So -
* Remind me when the route via Acton is closed too?
* When does HS2^▸ (The next High Speed line(s)) open to provide extra capacity for the West Coast line?
* Am I the only one that wonders why this wasn't picked up into some sort of planned engineering more mearured than a PANIC!

[stuving]

* Am I the only one that wonders why this wasn't picked up into some sort of planned engineering more mearured than a PANIC!

We know they were monitoring the subsidence of that southern abutment, and no doubt working on a plan. One part of the planning would be to decide whether it's just the abutment that needs to be fixed, or whether the bridge spans have such a limited remaining life they should be replaced as well.

The timescale for this is based on its rate of sinking. So when it suddenly drops by a big extra amount in a short time, the planning process is instantly running late. And you can't keep sending in a stone-blower to hitch the track up for ever. The amount of extra ballast is getting embarrassing - a rough estimate says it's about 50 tonnes!

[IndustryInsider]

Flooding was the key to the enforced closure IIUC.  Had that not happened it would probably have been OK until the repair schedule that was planned arrived.

[bobm]

BBC^» (British Broadcasting Corporation - home page) South Today showed a couple of photographs from the bridge.  There was also a quote that an engineer could get his arm into the cracks.

[Electric train]

From the photos and other info I have seen in this thread my thoughts are the foundation of the Southern pier / abutment has been eroded by the river.  It has been seen on other parts of the network such as Feltham in 2009 failure of the structure can accelerate to collapse quickly even on bridges that are being monitored.

* Am I the only one that wonders why this wasn't picked up into some sort of planned engineering more mearured than a PANIC!

We know they were monitoring the subsidence of that southern abutment, and no doubt working on a plan. One part of the planning would be to decide whether it's just the abutment that needs to be fixed, or whether the bridge spans have such a limited remaining life they should be replaced as well.

The timescale for this is based on its rate of sinking. So when it suddenly drops by a big extra amount in a short time, the planning process is instantly running late. And you can't keep sending in a stone-blower to hitch the track up for ever. The amount of extra ballast is getting embarrassing - a rough estimate says it's about 50 tonnes!

 

If a renewal or major structural refurb perhaps in CP7, it almost certainly would involve a number of blockades; which in themselves are planned 4 or more years out.