Plans to rebuild a railway bridge at Pangbourne - don't blame Network Rail

[whole diary]

[paul7575]

No, nothing to do with the Reading works - I'm not that familiar with the lie of the land, but it would be well west of the Reading area. Two separate brick arches over the mains and reliefs - but anyone who passes that way regularly ought to be able to picture the temporary bridge, which is on the Reading side of the bridge being worked on - another visual cue might be the stacked gabions (those wire mesh cages full of stone) supporting the temporary embankments.

PS - the major works for the flyovers at Reading West Jn aren't even due to start until after the station is done, Chris...

Paul

[willc]

I was reminded of this old thread about bridge re-building because I was on a XC^▸ (Cross Country Trains (franchise)) service on Monday that went under at least one brick arch bridge between Didcot and Reading which seemed to be in the middle of a major building site, with a temporary overbridge alongside it.  I thought it was probably the one under discussion here?

Then this week's Rail magazine reported that gauge clearance on the route between Southampton and the Midlands is finished, and trains are running with larger containers on normal wagons.

So if the clearance work really is still ongoing, how can the W10 traffic be running already? 

 

Paul

Simple really - because the new bridge spans are in place, or the old ones are removed at least, so the required headroom is available for trains carrying 9ft 6in boxes on standard flat wagons. The work going on at present is mainly finishing off and reinstating roads, mains pipes, telecom ducts, etc, etc. I know two bridge sites still being worked on are the Old Abingdon Road in Oxford (to reopen to road traffic by the end of the month) and near the Leatherne Bottel restaurant, between South Stoke and Goring. Could be others nearer Reading as well.

[paul7575]

To clarify this - the bridge I'm talking about doesn't look as though it's had the original arches removed, they are still the brick they've always been.

This site isn't comparable with others (like the one in Oxford still ongoing) where they've removed the main part of the bridge back to the springing points (the verticals), and reinstated them with massive concrete prefabricated sections - it is still a pair of brick arches.

Unless it has been rebuilt in the original brick?

Between South Stoke and Goring seems about the right area by the way, looking at the map.

Paul

[willc]

The other option, which has been adopted by Network Rail where it was possible, was to lower the level of the track under the bridges. Given that the hi-cube trains are running under this bridge suggests that was the case here.

[paul7575]

I thought that was a possible explanation, but it wouldn't explain why they went to all the bother of a temporary bridge alongside, with some pretty expensive looking earthworks? 

Paul

[Tim]

Does this gauge clearance work give any advantage to passenger services?  I don't suppose the extra height is enough to make double deckers viable or anything like that but as more of the network is cleared for these high cube containers will we ever see more spacious passenger saloons as a result (or more space on the roof for aircon etc allowing the floors to be lower)?

[IndustryInsider]

Simple really - because the new bridge spans are in place, or the old ones are removed at least, so the required headroom is available for trains carrying 9ft 6in boxes on standard flat wagons. The work going on at present is mainly finishing off and reinstating roads, mains pipes, telecom ducts, etc, etc. I know two bridge sites still being worked on are the Old Abingdon Road in Oxford (to reopen to road traffic by the end of the month) and near the Leatherne Bottel restaurant, between South Stoke and Goring. Could be others nearer Reading as well.

I find it slightly strange as well, given that the bridge near South Stoke is still in situ.  There's been a temporary bridge installed there for a couple of months now, but no major work undertaken on the old bridge visible and the spans are very much still there.  No sign of any track work either and it looks pretty certain to me that the old bridge is destined to come down.  Track has been replaced/lowered on the bridge between Pangbourne and Tilehurst in the down direction though.

Perhaps it's just the main lines that have been authorised - pending final works on the reliefs, as the arches are higher over those as they used to span broad gauge track?

[paul7575]

Does this gauge clearance work give any advantage to passenger services?  I don't suppose the extra height is enough to make double deckers viable or anything like that but as more of the network is cleared for these high cube containers will we ever see more spacious passenger saloons as a result (or more space on the roof for aircon etc allowing the floors to be lower)?

W10 doesn't give really give any significant extra height for passenger vehicles, IIRC^▸ (if I recall/remember/read correctly) it's mostly about clearing the top corners of 'boxes'. (In comparison to the more rounded lines of carriages or MU^▸ (Multiple Unit) vehicles, IYSWIM.)  Much of the gauge clearance work for W10 involves getting rid of arches, but the replacement beams or slabs are not usually much higher than the crown of the original arch.

I'll see if I can find a drawing later...

Paul

[willc]

Diagram here http://www.btinternet.com/~joyce.whitchurch/gauges/text.htm

[paul7575]

Diagram here http://www.btinternet.com/~joyce.whitchurch/gauges/text.htm

Thanks for looking that out willc, saved me doing it. 

What I'd add is that Network Rail consider that C1^▸ ((on coaches) National route restriction) and C3 coaching stock has a nominal height of 3.774m, which is within only a few inches cm of W10. 

Edit:  never mix units, as my science teacher once said...

Paul

[Tim]

Thanks for the explanation. 

[paul7575]

I find it slightly strange as well, given that the bridge near South Stoke is still in situ.  There's been a temporary bridge installed there for a couple of months now, but no major work undertaken on the old bridge visible and the spans are very much still there.  No sign of any track work either and it looks pretty certain to me that the old bridge is destined to come down.  Track has been replaced/lowered on the bridge between Pangbourne and Tilehurst in the down direction though.

Perhaps it's just the main lines that have been authorised - pending final works on the reliefs, as the arches are higher over those as they used to span broad gauge track?

Did some digging on this, as it's been niggling away...   

There are two planning applications on South Oxford's website:

http://www.southoxon.gov.uk/ccm/support/Main.jsp?MODULE=ApplicationDetails&REF=P10/W1340&TYPE=Application

P10/W1340 - approved on 14 Sep 2010

and http://www.southoxon.gov.uk/ccm/support/Main.jsp?MODULE=ApplicationDetails&REF=P10/W1833&TYPE=Application

P10/W1833 - approved on 21 Dec 2010 - apparently following minor changes at NR^» (Network Rail - home page)'s request.

Still can't find anything online that mentions any external reasons for the apparent delay, it could be that with an original track possession date missed, there's an inherent delay to re-book it, or perhaps there's no heavy lift capacity available?

However some detailed drawings amongst the online applications do confirm that the existing 'main line' arch has significantly more clearance than the relief arch, basically due to its extra width - so that seems to be the likeliest answer to how they've started running hi-cube services.  Modern Railways has also now reported the 'project completion'... 

Paul

[IndustryInsider]

However some detailed drawings amongst the online applications do confirm that the existing 'main line' arch has significantly more clearance than the relief arch, basically due to its extra width - so that seems to be the likeliest answer to how they've started running hi-cube services.  Modern Railways has also now reported the 'project completion'... 

I'm pretty sure I've seen some hi-cube's running on the Relief lines as well in the last few weeks though.  After I made that initial suggestion, I also thought about the consequences of the driver/signaller forgetting and thought that for safety reasons alone such a restriction would be unlikely to be authorised?  Still, there's no speed restrictions and the original spans remain in place, so it is a bit of a mystery!  I then thought that it might just be an unrelated bridge replacement and just coincidental, but Paul's links clearly state W10 as the reason.

Regarding the other bridge, which this thread originally refers to between Pangbourne and Tilehurst, I remember NR^» (Network Rail - home page) moaning that a decision on demolition had to be made in a certain amount of time, or there would be costly and disruptive alterations to the height of the track needed instead, so perhaps the decision wasn't taken in time.  But it seems the costly and disruptive alterations only amounted to one track being lowered over a couple of weekends (when other relief line work was also undertaken if I remember rightly) and so you then have to question whether NR was right to press for demolition of the bridge with that being the case?

[IndustryInsider]

Details on the scheme to provide a diversionary route from Southampton should the main route via Winchester not be available.

http://www.theconstructionindex.co.uk/news/construction-news/network-rail-announced-plans-for-rail-route-upgrade

[paul7575]

The updated CP4^▸ (Control Period 4 - the five year period between 2009 and 2014) enhancement plan has a detailed list of all the structures on the route, presumably because these are NR^» (Network Rail - home page) funded works. 

The work required for the main route was never really mentioned in detail, perhaps because it wasn't really an NR funded package, ie it was outside the HLOS^▸ (High Level Output Specification)? 

Edit:  The NR press release also has more info, with details of public road closures and dates of some fairly lengthy periods of weekend engineering work:

http://www.networkrailmediacentre.co.uk/Press-Releases/PLANS-ANNOUNCED-FOR-SECOND-RAIL-FREIGHT-UPGRADE-FROM-SOUTHAMPTON-176a/SearchCategoryID-8.aspx

Paul