Yes, I would imagine so.  A short 50mph restriction from a 90mph line speed won’t cause too many problems.

Yes, I would imagine so.  A short 50mph restriction from a 90mph line speed won’t cause too many problems.

Yes, I would imagine so.  A short 50mph restriction from a 90mph line speed won’t cause too many problems.

Is that likely to be there just until they’ve completely demobilised from site?

50mph TSR.

Did a return Didcot - Oxford today; noted that trains are running at reduced speed over the bridge.

Friday 9 Jun 2023
Rail passengers on the move again through Nuneham as major project to replace 160-year-old viaduct support completes ahead of schedule

Engineers have worked around the clock to safely reopen Nuneham Viaduct, in Oxfordshire, a day early, on Friday 9 June, following an intensive ten-week programme of work.

The railway between Didcot and Oxford was closed on Monday 3 April after significant movements in the viaduct were detected due to emerging structural issues with the south bank abutment (structure that supports the bridge). The abutment was built as part of the original viaduct in 1856.

The rail industry, including Great Western Railway (GWR), Chiltern Railways and CrossCountry, worked closely to keep passengers moving during the closure, whilst Network Rail’s engineers and contractors at Balfour Beatty carried out emergency repairs, which completed, ahead of schedule.

On Friday 9 June, the first passenger service to cross the viaduct in just under ten weeks was a GWR shuttle train between Oxford and Didcot. A full timetable for all train operators is planned to resume from Saturday 10 June.

A major project

Around 800 people have worked nearly 60,000 hours, to successfully install the new steel support, which will secure the future of this important rail link for generations to come.

In the final week of the major project, the 150-tonne bridge was lowered onto the new abutment, a new embankment built, before the railway tracks and cables were put back in place.

The repair of the viaduct has been complex, challenging and required some heavy engineering:

    24 x 15m long steel piles were driven into the bed of the River Thames to create a solid platform for the temporary structure that held the weight of the viaduct while the abutment was demolished and rebuilt. 
    Eight more piles were driven up to 20m into the embankment to support the new structure.
    A 750-tonne crane was used to lift the temporary structure into place.
    4,500 tonnes of material removed from the old embankment 
    5,500 tonnes of material brought back in to build the new embankment

Engineers will remain on site for up to 12 weeks to finish works and demobilise the construction site, working outside of train operating hours, whilst track, signalling and station upgrades continue in Oxford city centre*...

Notes to Editors

*From Saturday 29 July until the early hours of Monday 7 August Network Rail will be working to upgrade the track just north of Oxford Station - installing new high speed crossovers. To the south of the station,  Osney Lane footbridge will be modified, moving one of the piers to make way for track layout changes. Work will also be carried out to adjust the coping stones on platforms inside the station.

07:10 Oxford to Didcot Parkway due 07:27

An additional train service has been planned to operate as shown 07:10 Oxford to Didcot Parkway due 07:27.

Think there's a couple of those fastenings lying spare on the deck and they may or may not be called 'Carriage bolts'.

Mark

Attached is a classic example. The 1857 original timber bridge on the GWR Weymouth line was simply covered over when the line was doubled in the 1880s.

Then in the late 1980s it was rebuilt again, this time to provide clearance for the western arm of the Dorchester bypass(A37). I was called in by Dorset County Museum and was shown the site, after the line reopened, there is still timber buried there.

British Rail kindly gave the Museum and myself copied of the photographs they had taken, one of which is seen here

Sorry - my mistake.

A note about dates: Stuart Calvert talks about the "1856 timber structure"

Sorry - my mistake.

A note about dates: Stuart Calvert talks about the "1856 timber structure" - but the original timber bridge was built in 1843, and by inference its abutment was reused in 1856 and 1916 for the two iron bridges. The GWR magazine (posted earlier) only said it was "constructed under the Oxford Railway Act, 1843", and was "replaced in 1849-50". So who's right? I've been looking for old newspapers...

I have just found a piece in the Berkshire Chronicle of 11 November 1843 saying that the first Nuneham bridge started building "on Saturday, and will be completed in about five weeks." As the 11th was a Saturday, that start date was the 4th. I can't find completion recorded, but the line was opened on Wednesday June 12th 1844, and the "journey is performed in something under two hours and a half" (London-Oxford).

For the second bridge, there is a detailed report (Oxford Journal Saturday 20 September 1856) of the inquest into Henry Collett's death by drowning in the Thames. He was a labourer working on the new Nuneham bridge, and "late of Appleford", and several workmates gave evidence. He was last seen alive on Tuesday 9th September, and found under the new bridge on Monday 15th. We don't know from that how long the work took before and after, but those Victorians would likely not need all of a year for that job.

There was another inquest, into the death of a young lad working on the new bridge at Appleford, and that happened in July 1856. So it appears both bridges were rebuilt in wrought iron at the same time. If they were built the same way, at the same time, in the same river, it is pretty likely they both needed replacement together, and of course if the line has to be closed you'd rather do both within one closure.

That link doesn't work - it seems to have some '%' signs embedded.

New parts, stringers, cross members may be being fabricated to match the new bearings,

Exploiting the super-zoom facility of Flickr, you can see what they have done in one of yesterday's pictures. There are two longitudinal members under the deck on each side, resting on the crossbeams. Because of the skew (very clear in today's overhead view) they extend varying amounts beyond the last crossbeam. These stringers are made of short pieces joined by riveted plates, and it looks as if the end piece has been unriveted in each case. While it's hard to see, I think the end crossbeam meets the western (far) side girder right at its end, so part of this must have been unriveted as well. (Yes - that's visible in one of today's pictures.)

Images from Network Rail on Twitter show the progress with the row of piles, they basically line up with the ends of the three main girders, it looks like a small area of deck plating has been removed for vertical access:

Images from Network Rail on Twitter show the progress with the row of piles, they basically line up with the ends of the three main girders, it looks like a small area of deck plating has been removed for vertical access:

https://twitter.com/networkrailwest/status/1658843943038009349

I’m surprised they’re saying it’s just starting today 17th, given the previous photos taken on the 15th…

Paul

If you draw a line between the ends of the two side beams that's true. I think the centre beam is longer than the side beams, so that each half deck ends at right angles to the bridge axis. You can see this, just about, in other parts of the video. How else would you do it?

Is it the case that this aspect of the steel spans at Nuneham is rather peculiar and possibly uncommon?

Mark

Is it the case that this aspect of the steel spans at Nuneham is rather peculiar and possibly uncommon?

Mark

Interesting that the central beam appears to project further back into the the abutment than either of the side beams.

... and in the middle of the ends, made more complicated by the skew and the resulting stagger between the two sides.

... and in the middle of the ends, made more complicated by the skew and the resulting stagger between the two sides.

... this type of bridge where the load is transferred at the corners of each deck. 

Moving earth around has got so quick and easy with modern machinery that I don't suppose it's a big issue any more. You have only to look at any building site, even a couple of houses, to see how much moving earth back and forth goes on and how few people it takes to do it.

So I think it looks like working space they are creating. I'm sure there will be very strict rules and restraints to prevent anyone working underneath that bridge of Damocles. Incidentally, I've seen no sign of anything holding that span in place, to prevent it moving on or off its bearings or the jacks. Surely that's essential in a case like this?

New Friday video from Network Rail Western.

https://twitter.com/networkrailwest/status/1657030370897055744

I'm no closer to understanding how that bridge's bearings work. We could do with a few close up quality photos of the, um, ends.

Mark

I wouldn't have thought the embankment would be cut back further than absolutely necessary - to do otherwise would increase the cost and duration of the repair -  so somebody must surely have concluded there is an awful lot of unstable ground around the south abutment.

Possibly, though the trusses are only supported at the ends so there is quite a long span. The loads may not be evenly distributed among all the jacks that support the deck or if there is some differential settlement in the piles. There will also need to be some allowance for accidental and construction loads on the bridge deck.  Finally they will be using what they had available in the yard at short notice. 

See last two pictures for an idea of how much of the embankment has been removed at this stage
https://www.tmsmaritime.co.uk/emergency-works-2/

For those that can see that picture ... doesn't the platform the jacks are sitting on - piles, lattice girders and all - look massively over the top for the load they are carrying (which is about 120 tons total)? Even if it's rigidity that counts, rather than strength, that's still true.

[...]

Depends if anyone else can see the image which is the one that Red Squirrel posted

Is this the problem I describe at http://www.passenger.chat/27456 ?

600mm. Blimey. Impressive.

Here's the picture from Twitter:



Well I tried.  Why can I only get that to work 50% of the time?

I was going to add that that is just as I imagined it would be done. 

Now the real work can start on the new abutment. 

From what Stuart Calvert says at 1:18 I wonder if they are going to make openings in the bridge deck so they can insert the piles and drill down through the deck from above.

If this is so the deck will be jacked up slightly so the new abutment can then be constructed underneath it before the deck is lowered down on to its new bearings.

For the abutment, I can see that removing the embankment will allow them to put piles in just beyond the end of the bridge, and they can also put them beside the bearings. That could give enough support and keep the load through the piles vertical (which I think helps). The bearing for the middle girder is the difficult one to get under or all around. 

Something has gone wrong somewhere though, hasn't it? Bond Street (Elizabeth line) and Portway Park & Ride stations have little in common on the face of it, but both seem to have faced months of delay due to certification issues. I'm told that a couple of local reopenings have been delayed by a lack of awarenesss of certification requirements.

...naval gazing...

I see no ships.

[...]

The naval gazing is generated by a whole load of "governance" place on NR by the the Treasury and the DfT and the ORR and some internal.  NR is a large "public" body that spends a lot of Tax payers money which means there will always be rules governing how it spends money; after all Contractors mainly have to look after their share holders interests.

[...]

Well, yeah.

I have an engineering background (mechanical rather than civil) so I do understand that there is a lot more to these things than meets the eye of the lay observer. But even in the exciting new world of Project Speed, I can't help thinking that the general modus operandi is still far too omphaloskeptic.

Also, there must be someone in Network Rail just itching to take the opportunity, while that span is lifted off its bearings and free of ballast, for a full grit blast and application of fetching (and black) epoxy surface coating to Nuneham Bridge's rusting steel.

Mark

The uncaptioned chap from NR said:

"We'd normally spend 2 or 3 years in planning and designing and getting everything organised"

This situation is very abnormal for a number of reasons, but one can't help wondering if other projects could move forward quicker if there was a greater sense of urgency...

omphaloskeptic.

Known as ‘JFDI’?…..

According to BR Fares, no ... virtually everything is "any permitted". I suspect there may have been some sort of agreement as Chiltern were allowed to enter Oxford that they would not undercut GWR?

Wouldn't that be illegal as anti-competitive behaviour.  I thought the whole idea of competing services was to introduce competition!

Paul Clifton’s piece for Rail magazine has a very intresting snippet.

GWR tell him that since the pandemic, there are just 112 season ticket holders from Oxford. And around just 1,500 peak passengers on most days.

According to BR Fares, no ... virtually everything is "any permitted". I suspect there may have been some sort of agreement as Chiltern were allowed to enter Oxford that they would not undercut GWR?

Is there a season cheaper via High Wycombe only? If so, I imagine there are a lot more OXF-LON seasons.

How do you pile into the bed of a river anyway? It may be closed, but the water is still there, and I've seen no mention of a coffer dam. In this case, would you use very long piles (joined if need be) so the tops are above water - and have to cut them down to free the river for reopening? Or would you drive the piles flush with the river bed, using a suitable piling hammer (which I see are standard pieces of kit), and bolt on the trestle underwater?
 

I wonder if those piles are going to be used to temporarily support the spans while the abutment is repiled and rebuild. The temporary piles will not have to support any dynamic weight unlike the abutment.

Looking at the piles stacked up they look like the type and style used for OLE masts; I wonder if they are making use of the Didcot - Oxford electrification piles that were not driven into the ground before the electrification was stopped

Another update from Network Rail…

https://twitter.com/networkrailwest/status/1649077107660652547?s=46&t=ah-SsHksqViJs35eOx7jsQ

East West Rail construction site I think, not too far from Quainton Road of the Buckinghamshire Railway Centre.