This thread has been extracted and regrouped from several others including
http://www.passenger.chat/14689 - Infrastructure problems in Thames Valley causing disruption elsewhere - ongoing, since Oct 2014
once the severity of the isse became apparent

The bridge over the Thames between Culham and Radley now appears to have a temporary speed limit of 5mph. This is adding about 4 minutes to each journey.

Hopefully that won't be lowered to 0mph before the work has finished.

Edit to add introductory paragraph - grahame

 
Seems like I spoke to soon as the bridge at Culham has now been closed.

GWR are saying for rest of the day (3rd April), but I would like to know if that is realistic and is it really going to be longer?

Passengers from Didcot to Oxford asked to catch local buses.

 
Could be weeks apparently!

 

Oops!

Advice on Cross Country from National Rail:


Interesting that no cross-availability on GWR ... So if I have a Bounemouth to Oxford advanced ticket (are there such things?  I must travel Bournemouth to Southampton on an XC train, but I can then use SWR to Waterloo, tube to Marylebone, and Chiltern to Oxford.   Not allowed to use XC from Bournemouth as far as they are running and the GWR to Didcot and bus to Oxford.

 
Due to urgent repairs to a bridge between Didcot Parkway and Oxford all lines are closed.
Impact:
Train services running through these stations will be cancelled or suspended between Didcot Parkway and Oxford. All stations between Didcot Parkway and Oxford will not be served. Disruption is expected until the end of the day.

There appears to be an attempt to get RRB going. Cross Country Trains look like they're being turned at Reading and Birmingham.

 
Half term means buses are easier to get hold of thankfully!  As mentioned on another thread it could be a closure of a couple of weeks.

 
Their is major freight through there too ...  diversion via Greenford, or via Cheltenham, or something else??

 

Could that be because they are hoping to run Bournemouth to Didcot, like they were on Sunday? Although looks like only Bournemouth to Reading at the moment.

Even if they didn't run to Didcot, I would be tempted to catch XC to Reading then bus to Oxford, especially as the extra cost would only be £2. Going via London would be mad.

 

Container traffic to/from Southampton (which makes up a large portion of freight traffic over the route in question) is being diverted via Reading, Acton Wells and the WCML to its onward destination.

Colas are sending their traffic via Bristol and Bromsgrove.  Not sure about DB yet.

Other traffic such as Stone traffic to/from Oxford Parkway and car traffic to/from Morris Cowley will cease for the immediate future.

This is all short term, quick fix stuff.  No doubt a more concrete plan will emerge once more details about the situation and longevity come clear.

 
I expect a “more concrete plan” might be a big part of the fix for the Thames abutments too…

 
Local press now suggesting that it will be closed for at least 3 weeks for temporary repairs.

 
From the 'Oxford Clarion' on Twitter:
https://twitter.com/OxfordClarion/status/1642904141495169024

 
I’m assuming “one of the brick arches” either means one of the land abutments or the river pier, I think there are only 3 in total?   The river pier is an arch structure along the line of the river, but I haven’t seen a view of anywhere else.  So presumably if it’s the river pier timescales will be more significant?

Paul

 

Freight + the Lickey incline in the present day: what does that involve please, anyone?

Mark

 
I'm guessing it's the abutments on the southern side of the bridge - that's where the NR work team seemed to be when I passed that way last week. But I may be wrong.

 
There's a lot of confusion over whether this is a bridge or a viaduct (and GWR used to call it Newnham, as well). The replacement for the original timber structure had steel plate girders resting on six sets of columns (piers, in effect), spanning the river and the ground on the Oxford side. That was replaced in 1906 by the present bridge, and three "piers" were removed from the river and replaced by one pier, since the bowstring girders are longer. The next support was replaced by a pier of the same design, leaving three of the old spans and two "piers" as the viaduct part. Lots of details about that is this document, including how it was done (mostly closing one line at a time).

However, now that viaduct is made of three brick arches - as seen in this geograph photo. (I think getting to where that was taken was probably quite a struggle.) But I've no idea when that happened - and which bit is now subsiding?

 
Ah, the photo that stuving has found shows there’s a few more areas that might be the failure site. The aerial photos don’t really give you any idea that’s there still some brick arch viaduct in use.

Paul

 
Now being featured on BBC local news - apparently closed for at least two weeks. Paul Clifton reporting - NR to make announcement tomorrow

 
When I passed on Saturday, at walking speed, there was a haul road to the site and some people on/next to site.

At the moment I think the main problem will be the state of the river. River is above normal

https://check-for-flooding.service.gov.uk/station/7097 [NOTE: this is a live link so will change depending on when you see it]

and the current river conditions


https://www.gov.uk/guidance/river-thames-current-river-conditions#current-river-conditions-updated-3-april-2023 which means

 

Yes, on both sides, I think. You can get a bit more of a peek from below with Google Street View, which has the view from the Thames Path on it.

 
This was the main story just now on BBC South Today with Paul Clifton. There was some video showing that one of the two spans is definitely out of vertical alignment. He said that NR staff are currently not at the scene and there's no comment from the company as to the exact nature of the problem. He expects them to make a statement tomorrow.

 

Ah, so it is not so inaccessible. You can also see the piers of the viaduct arches on satellite view - just, once you know where to look. But that is only on the north side, and it is the newest part of the structure, and the problems before 1906 were all in the river. So maybe when they went down "11 feet below the river bed to the Oxford clay" that wasn't enough.

 
Paul Clifton an hour ago https://twitter.com/PaulCliftonBBC

 
What I see in those BBC pictures (however reliable that is) is that the transition pier on the north bank has dropped. That makes historical sense, if that bit was not seen as a problem in 1906, so its foundations don't go down as far as the one in the river bed. Since then, with the disturbance of having the viaduct rebuilt, and a heavier pier and bridge to support ...

I find it hard to believe that the water table that close to the river has changed much.

 
GWR has now been added to the list on the National Rail page mentioned earlier, about XC ticket acceptance following the failed Nuneham bridge/viaduct…

Paul

 

There has been a lot of gravel extraction and subsequent land fill in the last few decades, I wonder if this has impacted the water table.

 
I have found one newspaper reference to the rebuilding of the viaduct, and that's from a "last year's work" summary in January 1931, and is as curt as: "the north end of Nuneham viaduct, Culham, [has been] reconstructed".

From the Thames Path, you can see that the arches piercing the pier on the north bank were filled in when that work was done. But there is no sign on distress in the pier itself, nor what little you can see of the arch attached to it. So maybe that isn't quite so likely as an explanation. You can also see the bearings of the bridge, which are not exactly sophisticated, and how the skew on the bridge complicates the one on the left (west) side.

 
Thoughts with all affected.

Cancellations to services between Reading and London Paddington

Due to a person hit by a train between Reading and London Paddington all lines are blocked.

Train services running to and from these stations may be cancelled or delayed. Disruption is expected until the end of the day.

 
I've now seen a picture on railforums that I think is of the west wing wall on the south bank, and this really is distressed. It's just at the very right of the BBC's shots, and out of sight looked at from above. But you can see that the parapet pillar (supporting the fence rails) is decidedly wonky. A drop in that bearing would, of course, give the same angle at the mid-river pier. You can also see how deep the ballast bed on the bridge has got over the years! Do you think that was to compensate for this drop?

I do hope these guys have not become so specialised that NR have only got one wing-wall team.

 
Moderators - can I suggest that the Nuneham/Culham viaduct problem merits its own thread, rather than being split between two general delay threads as at present?

 

Now 3 weeks according to JourneyCheck



If another of the mod team can sort this out as suggested - THANK YOU.  My connection keeps dropping and is very laggy ...

 
Noting Euston to Milton Keynes closed over Easter too. Southampton to Birmingham, Derby, etc., passenger might do better via Bristol?

 
(It might not be easy to pull posts from at least two other threads into this one - if that's doable, other mods, please kill this one.)

Nuneham Bridge, the third bridge on the site, is a two span steel bowstring carried on two abutments and a central pier in the river, dating from 1907. On the north approach, the line is carried on several brick arches, on the south, an embankment.

The southern abutment has subsided over a period of months if not longer, additional ballast has been used to keep the line useable albeit with a speed restriction. At the start of April the abutment's subsidence continued to worsen and it was necessary to close the line completely. As of April 4th, a date at which it can be reopened has not been announced.

Mark

(Edited to correct the date that the current bowstring spans replaced much of the previous bridge. Wikipedia had this as 1929 so, corrected Wikipedia too...)

 
I've launched a new thread in the appropriate forum topic. If that doesn't help, mods, please do delete it.

Mark

Edit - You can find that thread ((here)) - grahame.

If I have decent connectivity during tonight, I'll back up databases and see if I can do some splitting and merging while the forum is quiet, but if the connectivity is poor I may have to leave it until back on dry land.

 
Updated now to be after easter

https://www.networkrailmediacentre.co.uk/news/passengers-advised-to-check-before-travelling-as-railway-between-didcot-parkway-and-oxford-to-remain-closed-until-after-easter

Though GWR is still quoting the end of the day

 
Paul Clifton has posted two good aerial photos to Twitter. Do they perhaps show that at the south abutment, the ballast in an indication that the abutment continues to subside, is retreating beneath the track?

In another, he says "...privately I’m hearing the closure will be months, not weeks."

Mark

https://twitter.com/PaulCliftonBBC/status/1643216802032353281

 
NR saying shuttle services are to be run Oxford -  Radley and Didcot - Culham.

Shame they can't run up to the bridge, where we can walk across and get on another train on the other side; that would be quicker than taking the bus 

And yes I understand all the issues about why that wouldn't happen.

According to Google would take 26 minutes to cycle between those two stations!

 
On the bright side, the Environment Agency's not yet closed the river navigation beneath the bridge.

Paul Clifton's images are quite stark: the first actually shows that at the abutment, the ballast is retreating beneath the track, in a short time it looks to have dropped by about a sleeper's depth.

Adding some straight lines to his second photo just about starts to reveal the extent to which the southern span has subsided. The weight of the additional ballast added to the span can't be helping at this point. One of the yellow lines tracks a railhead, the other, the ends of the floor beams of the northern span projected across the southern span.

Mark

 

I've merged the three (!) separate discussions on this.

Some of the interim topic names are still around and I can't see a way of changing them in bulk. grahame, if you have a moment (and the connectivity!) to do an UPDATE later, that would be the cherry on the cake.

 

Done  (that was the easy bit!)

 

Thanks for this. The Culham Ticket Office site's copy of the article from the 1908 GWR Magazine's photo of the then new bowstring arches (both of which are good and level)

https://culhamticketoffice.co.uk/bits/hidden-pages/nuneham-bridge.html

That photo also shows what looks to be a couple of remaining spans from the previous viaduct still in use on northern approach - if that work was finally replaced around 1929, that date of '1931' combined with 'Last year's work' might be the origin for the erroneus 1929 date for the bowstring spans as given in the likes of https://www.thames.me.uk/s01530.htm

Mark

 

I think that sentence on thames.me.uk (which also says the new bridge in 1929 had one span) has been misplaced, and should be on the Appleford bridge page. The two bridges (or viaducts) are near-identical twin sisters, in each of their three incarnations.

The Culham Ticket Office site also has a GWR magazine page about Appleford, which explains that the work was meant to start in 1927, but was delayed until 1928 by guess what - flooding!. It was completed in 1929, suggesting that the more recently something like this is done, the longer it takes.

There are subtle differences in the design and working method, as well, though in both cases the bridge spans were rivetted together on site, with the girders placed on the piers first and then the cross members added in situ. At Nuneham, the outer girders fitted on the ends of the piers, and I think the middle one went in the gap between the two original one-track bridges (which may explain its different design). One track was closed and demolished and the replacing half assembled, then the other half was done. At Appleford, where the three girders are the same, they built the piers and the first half just to one side, with both tracks still in use. Then they demolished just one old bridge of the pair and finished the new one, still with two lines in use. So the track at each end has moved sideways, though I can't see any trace on the satellite views of that now.

 
Ah, that's another find, thanks for this.

Mark

 
Big THANK YOU to Rchard for doing the lion's share of reforming this thread from disparate others which had content on the topic in them, and to Bob for icing the cake by fixing topic names.

Other topics include
http://www.passenger.chat/14689 - Infrastructure problems in Thames Valley causing disruption elsewhere - ongoing, since Oct 2014
where posts on other infrastructure problems still "belong?

 
Now updated to "at least" 23 April.


Cancellations to services between Reading/Didcot Parkway and Oxford until at least Sunday 23 April
Following a safety inspection of a railway viaduct between Didcot Parkway and Oxford the railway has been closed to allow emergency repairs to take place. We are expecting this work to continue until at least Sunday 23 April.

 
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

 
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

 

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).

 
Most likely water, but could be gas. 

 
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

 

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.

 

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

 
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 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 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.

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

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

 

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 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!

 

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!

 
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.

 
BBC 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.

 
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.

 

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. 

 
It will be interesting to know more about the date of construction of that abutment, how it failed - and why it failed now.
 
Perhaps the structure of the abutment dates largely from the line's original construction - 1843. A photo carried by Wikimedia shows that it was showing signs of distress in 2018.



Since then there's been the continuation of the odd flood, and last year, unusual heat followed by unusual spells of cold weather - and as the structure moved,  the track ballast added to the span produced an additional wedge shaped mass that increasingly loaded the abutment. (It's been remarked that the railway has a bit of a blind spot when it comes to ballast depths on structures generally, though this is a special case...) In any case, this doesn't appear to be vertical subsidence - if the abutment is rotating as its foot moves in the direction of the river, whatever force that propels that rotation will increasingly be helped along by the mass of the bridge bearing on the abutment from above.

Speaking of bearings,  there's then the issue that as well as being wrung by being potentially twisted, if that span has only sliding bearings that do not allow for rotation, those may be at risk of damage too, and at both ends of the span.

Mark

 

Engineers really will put their arms into anything.

 
In this piece from the Oxford Mail on Tuesday, the story is by now familiar...

... but the picture from that angle shows some new elements. You can only see the top of the wing wall on the right, which has come away, but on the left you can see how badly cracked that one is lower down. Also, the river wall has been sinking, though more so on the left, and it has cracked.

This is another foreshortened view, making angles and depths hard to judge. For example, that signal is actually beyond the far track, and more than one bridge span from the end of the bridge.

 
Here are a couple of pictures of the damage - that's some serious structural damage by the looks of it!

I note this update too - Due to urgent repairs to a bridge between Didcot Parkway and Oxford the line is closed. Disruption is expected until the end of the day on 30/04/23.

 
Looks to me that it had the 1909 bridge support, the blue engineering bricks, built on top of the original 1843 brickwork.  It looks like at some stage in the past its had a concrete added as foundation repair.   The Victorian engineers did use wooden piles to build structures on, wonder if this is the case here the wooden piles have failed 

 

It does look like pile failure. I am not sure how they are going to repair that in two or three weeks.  a temporary support in the river doesn't look easy. Perhaps new piles on either side of the abutment and a beam between?

Whatever it looks like it needs an entirely new support. 

 
Very interesting aspiration being voiced locally that the permanent bridge should have an extra deck for walking and cycling:

https://twitter.com/LeyNathan/status/1644006919328219137

Together with the new road bridge being built over the Thames, that would make a north-south traffic-free cycle route of some 40 miles, from Witney, Woodstock and Hanborough, via Oxford, to Culham, Didcot and Wantage. Perhaps Oxfordshire County Council should start thinking now about oozegonnapayforit...

 
Whitchurch Bridge, which is a 44 tonnes metal decked road bridge over the Thames at Pangbourne, was reconstructed in 2014.  At the design stage it was established that the south abutment wasn’t strong enough, so a new abutment was constructed.  The geology and quality of the chalk was an issue, which may or may not be the same at Nuneham, but 3 X 900mm piles were required, sunk to a depth of 21 metres.

If new piles are required for a conventional abutment at Nuneham then the bridge deck will need to be removed to give clear vertical space for the drilling rig.  But maybe clever NR bridge engineers have another way of installing a new abutment, eg drilling piles either side of the bridge deck and then casting a beam between them, as Ellendune suggests.   


Edit to insert "metal decked".

 
The photo from Wikimedia has some of the same section of wall (and the same crack) but in 2018.

Mark

https://commons.wikimedia.org/wiki/File:Rail_bridge_over_the_River_Thames,_carrying_the_Cherwell_Valley_line_07.jpg

 

I like the way that a Clr makes demands  and not the County Council must work with Network Rail to ensure provision is made in any new works for ...........

I suspect that NR will have with the cooperation of the Environment Agency temporary steel work erected to support the Southern end of the bridge to allow trains to run albeit at 5mph over the bridge to allow a permanent piled solution.  

One thing which has not been made known have the bridge spans at their end of life or do they have another 25, 50, 100 years life?  Even if they are nearing their end of life replacing them I would suggest will be not for 4 or 5 years just to get the designs, manufacture etc done

 
There’s an example of rebuilt abutments at Ludlow, details in the linked article below, where they apparently piled outside and around the plan of the existing piers, the river span was also made slightly smaller:

https://www.apbgroup.co.uk/project/rail-bridge-replacement-river-teme-ludlow-1417/

For some reason though, I’d assume that for this sort of location, (Nuneham), local planners will be screaming about the replacement having to be identical to the existing…

Paul

 
Some thoughts from MarkA posts
earlier it was said that the geology was London Clay (?, but certainly clay). The British Geological Survey Regional Geology; London and Thames valley says, in relation to shrink swell effects of clay:

"Widespread structural damage from these causes occurred following the drought in the summer of 1976"

Somebody with civils experience will be able to say if this has any relevance to a river situation after the 2022 drought. (shoot me down if needed)

A quote from the Twitter feed:


presumably not happy with the Hanson Way from Didcot to Oxford, or thinks us cyclists need a two-lane tarmaced highway.

 

Ok I am a Civil Engineer - but not a geotechnical specialist. 

For the clay to shrink the clay the water content of the clay must reduce significantly. Given its proximity to the river - and assuming the abutment is founded below the river level - then unless the Thames had actually dried up during the summer (I think I would have heard if it had) then shrink swell is not going to be the issue here.

However, river valleys are complex things and I know there are worked gravel deposits nearby, so I looked at the 1:50,000 BGS maps on-line. By the river the Gault Clays are overlaid by Alluvium which can mean a whole mixture of things as the BGS says. 


In short without borehole data I would not like to make a judgement about what is going on in the superficial layers (which might go quite deep). 

I would hope the abutments are funded on piles down into the bedrock Gault clay (who knows) but if they were timber piles they might be failing.

 
All of this is very confusing for JourneyCheck.

 
Paul Cicton has posted a track-level photo. Too hard to extract on iphone, but here’s the link to his tweet

https://twitter.com/paulcliftonbbc/status/1644354152779198464?s=46&t=ygkNhLNzEU-LHuFemK3xJA

 
An informative short discussion and a couple of images from 11 months back here on Linkedin (which will try and persuade the visitor to create an account/log in etc...) & kindly flagged by Hamish Harvey on Twitter.

Some evidence that the bridge deck is/was managing to push the tops of the wing walls out - and then also the wing walls showing signs that the pier was sinking/moving.

Mark

https://www.linkedin.com/posts/simon-deakin-woods-718aa2107_xeiad-networkrail-isar3-activity-6934582807071506432-dl3M/

 

Does rather beg the question - how on Earth did Network Rail allow it to get into this state before action was taken given that the damage had already been noted and these pictures are almost a year old and even then showed some pretty dramatic issues?

I also saw Paul Clifton's pictures on Twitter - most alarming.

 

I am a geologist, and I agree with you.

I too suspect the failure of wooden piles to account for the recent rapid movement.

 

I am absolutely certain Network Rail Wales and Western Region Structures Asset Management team had a plan.  It is entirely plausible the subsidence has accelerated faster than they anticipated, yes the state of this abutment has been known about, there are quite a number of things that perhaps needed to be resoulved, like Environment Agency approvals for river access, land owner access (for site access) railway possessions / blockades; not to mention the design of the solution.  

NR Assets teams are not large in numbers of people, they are reliant on contractors who are managed by the Capital or Works Delivery organisations.  It could be argued why NR does not have own in-house expertise to do all this, its down to how the railways were privatised and the governance placed on it by the DfT and ORR
    

 
As discussed elsewhere there are other (probably many other) structures that appear long overdue for maintenance. I wouldn’t want the job of trying to guess which one was going to cause problems next…

 

Quote from a driver (with respect to Paul Clifton's pictures) "it’s looked pretty much like that for the last few months, with a steadily reducing speed restriction (90-50-20-5)"

Here's the view from space............

 

I think somebody has attached a comedy ‘hall of mirrors’ lens to that camera.

This is what it looked like three weeks ago without distortion from above or foreshortening from a telephoto lens.  Rather less dramatic.

 
For the record, JourneyCheck has added a week since I last looked ...
but still misses the extra text on the end "and probably for some time beyond".

 
There’s an Environment Agency closure notice for the southern span, lasts for a month, it mentions a pontoon will be present under the bridge, navigation limited to the northern span:


https://www.gov.uk/government/publications/nuneham-railway-viaduct-repairs-2023-river-restriction-notice/nuneham-railway-viaduct-repairs-2023-river-restriction-notice

 

That depends what you were looking for. In terms of estimating the vertical movement since (1) the bridge was built and (2) whenever the track was last levelled, there is not so much difference. I make the first answer about half a metre, and the second at least 10 cm (but neither is meant to be closer than +/- 30% at best).

Presumably Simon Deakin-Woods' picture, of 10 months ago, was before that last visit from a stone-blower, and I'll be returning to what that shows shortly.

 
This picture was in the Oxford Mail, but credited to Network Rail.


It shows two "long-range stone-suckers", and the pipes lead to one of those vacuum excavation trucks. Deballasting isn't really evidence of what the planned work is, as it's the first step in most possible plans.

There's another picture of just to the right of that, in railforums, that can be compared with the one we had from Linked-In.

You can't see much of the wing wall (shown by the BBC or in post #63), but you can see a steep slope down in the top of the embankment. The abutment's movement has led to shear strain in the soil over about three metres.

One the right, the "bearing" block sits on the abutment wall, while at the other side there is a column of brickwork so the bearing sits forward of the wall. That must be to do with the skew of the bridge; my guess is that the abutment wall turned out to be not parallel to the mid-river pier, and this gets over that problem. The size of that column does suggest that supporting the weight of the bridge was not a big deal, for the 1906 designers.

The left wing wall has failed in shear, but the vertical movement across it is less than two courses (20 cm) so well short of the full distance. But a lot of the outer half has been patched or even rebuilt. So I wonder if that got so bad that major reconstruction was needed, and more than once. When the brickwork is intact, with good strong mortar and engineering bricks, it can provide significant support to the abutment. Once it fails it can't, so that may be one reason for the "sudden" burst of subsidence recently.

If flooding is relevant, then like ellendune I don't see how that can have much impact under the abutment (and below the water table). Surely it is the embankment that is likely to be destabilised most by a thorough soaking. And it does take significant shear stress to produce the observed shear strain in settled soil, which is another upward supporting force for the abutment. Soggy soil is more mobile, so a lot of the supporting force disappears. In combination, the total reduction in upward force could explain the extra and rapid subsidence recently.

Incidentally, what looks like horizontal shear between the brick courses isn't due to any extra cause, it's just how shear works. The internal bricks feel much the same forces whether the shear is applied to the sides or the top and bottom. There's a more complicated, and rigorous, explanation of all this but it means resorting to tensors ...

 
At least with bricks, it is simple shear 

 
The Independent

 

The Independent seems to have misunderstood what "a lot of movement" in the bridge means:

 
National Rail Enquires now saying 9th June.

 

Only a matter of time before some “clever” journalist works out that covers Easter, the May Day bank holiday, the Coronation weekend and the late Spring bank holiday.   

 

I am sure that even now (if not already!) GWR & NR are creating imaginative contingency plans.......particularly for the Coronation weekend......

 

Given how long this line is going to be closed, surely it would be better to add some extra services from Southampton travelling up via the Trans Wilts line to Swindon and then along the line to Cheltenham. Expecting people to divert a long way west or east to Bristol and London, where there are huge numbers of travellers and very complex movements, is a recipe for ensuring they don't ever travel by train again.

 

I know I'm a great supporter of using the TransWilts for diversions, but can I please promote ... Stations from Bournemouth to Reading as "normal" then Didcot, Swindon, Cheltenham Spa, Worcestershire Parkway, before resuming regular route at Birmingham New Street.    Or as an alternative - Reading, then via South Greenford to Banbury where normal route is resumed?

 
In an article released today, the New Civil Engineer web site no less... (may or may not paywall itself) gives a very optimistic date to reopen as 'The end of April'... that's certainly 'by june the ninth' but I'm not sure that's what Network Rail meant in their own statement on the opening date at the weekend.

Mark

https://www.newcivilengineer.com/latest/reopening-hopes-for-safety-concern-nuneham-viaduct-shift-to-end-of-april-as-investigations-continue-11-04-2023/

 
Graham's suggestion


Sounds a a lot better than National Rail Enquires suggestion.


Normally if I leave Pershore at 07:44 I would get to Paddington at around 09:50

National Rail Enquires tells me that leaving after 07:00 the best I can do via Bristol Parkway is:

08:48    Pershore [PSH] - Worcestershire Parkway [WOP] 08:53 0h 05m

08:58    Worcestershire Parkway [WOP] - Cheltenham Spa [CNM] 09:14 0h 16m
   
09:32    Cheltenham Spa [CNM] - Bristol Parkway [BPW] 10:00 0h 28m
   
10:24    Bristol Parkway [BPW]- London Paddington [PAD] 11:44 1h 20m

So nearly 2 Hours later.

Via New Street to Euston is a bit better.

08:03    Pershore [PSH]- Worcestershire Parkway [WOP]08:08 0h 05m    

08:14    Worcestershire Parkway [WOP]- Birmingham New Street [BHM]08:45 0h 31m    

09:17    Birmingham New Street [BHM]- London Euston [EUS] 10:54 1h 37m

Only one hour late.

 
I know it is easy for us armchair railway controllers to make suggestions without knowledge of all the relevant factors, but wouldn't it be better to introduce an emergency timetable, combining the Swindon (or Paddington) - Cheltenham and Cheltenham - Worcester and beyond services instead?

 
GWR are saying that planners can only be updated to this Friday currently & the fault is being worked on.

As are services & timetables beyond Friday. It’s still a liquid situation. How about cutting the poor train planners a tad of slack?

 
CrossCountry seem to have decided that it’s best to halve the service northbound from Oxford, where they are currently starting of course, to once every two hours. 

 
In order to connect with the service up from the South Coast that tuns to Didcot. By the tie the RRS reaches Oxford, the northbound leaves.