Viaduct work steps up a gear

On a very hot afternoon I visited the west side of the main line by the scrapyard.  Last Sunday my car thermometer said 7 degrees outside  and I was wearing my winter coat.  Today it said 27 degrees and I was wearing just a polo shirt.  Fortunately I was not tempted to wear shorts as the nettles have grown up at an alarming rate!

 The shuttering has been removed from the first pier and it can now be seen it what must be its finished state awaiting the deck,

 Immediately behind it is another one being prepared.   The steel reinforcing is being built up ready for the shuttering. Behind that the formwork both sides of the main line for the piers to support the viaduct as it crosses the line.

A better view of the same formwork on the east side of the main line that has appeared since last week.  Three piers under construction can be seen to the left.  Well two can be seen, the third is behind the tree that has come into leaf in the last seven days.  You can see all three in last sunday's picture.

The last pier on the higher ground has had its base poured ready for the steelwork.  In the distance right of centre is the piledriver working on pier number one.  Another is working on one of the intermediate piers.  You can see how the viaduct will move quite quickly away from the main line before curving back to pass over it.

 A large section of the steelwork for the viaduct has been delivered in the last week.  Looking at it I think it might be the section that crosses the main line,  It has RSJs at both ends with a deeper section in the middle.  Although you can't see it, it is curved and the curve goes the wrong way so it will have to be turned before being installed.   I will keep an eye on line closures in the next few weeks so I can try and be there when it is lifted into place.  I am guessing this will be done over a weekend.

 End on shot.  I think it was delivered in two halves and is being bolted together on site.

 A shot from a different angle looking north.  This is the opposite end to my first picture.

 I took a quick look over on the east side of the main line.  Not much to report other than the spoil heap that had appeared last week in the former settlement beds was much reduced in height.  However the removal of topsoil from Wilbury Hill has continued as this picture shows.  Earthmoving equipment is parked up at the top right next to a large bank of topsoil.

I zoomed in so you can see the extent of the work.  In the foreground is route of the new line, soon to be built up with chalk from the hill.  The line of pegs crossing the centre of the picture is the haul road from the hill to the site.

Update Saturday 19th May

First visit for two weeks due to family commitments last weekend.  Vegetation is growing really fast due to the constant rain we seem to have been getting over the last two months.   Nettles especially have shot up in the last two weeks making access difficult in some places.  Will have to take a stick with me next time!  First picture is behind the scrapyard where the settlement ponds will be located to take the run off from the viaduct.  A Grand Central service was passing at the time. 

Looking north, the piledriver has moved even closer to the scrapyard, suggesting that there are not many piles left to finish.

I then moved up on to the triangle of land between the main line and the former Bedford branch.  This shot looks back south towards the scrapyard and the piledriver.  Although it is hard to make out, immediately left of the piledriver is the ramp being built up to access the former Bedford line embankment where the new line will move onto the viaduct.  Better picture later in the report.

Turning the camera slightly left, you can see the preparations for the last viaduct pier on the triangle.

And next to it, another one at a more advanced stage.

And here is one they prepared earlier! It is all starting to make sense now.

The heap of pile tops grows ever larger.

Moving north, formwork and steel reinforcing is going up for the pier immediately next to the main line.

On the other side of the main line, a line of three piers under construction.

I moved round to the bridge in Cadwell Lane by the scrapyard entrance.  Since my last visit the scrapyard has been taken over by a new company, judging by the signs that have gone up.  Reports of its imminent demise due to the railway works seem to have been exaggerated!!  A way to accommodate both must have been found.  More of the Bedford embankment has been stripped back to allow piers two and three to be constructed.  It has been removed right back to what would have been the the original embankment of the Great Northern in 1850 before the Midland added its bit in 1857.

Looking towards the piledriver through the site gates. The end of the support wing of the former Bedford line bridge is on the right. The viaduct will swing quite quickly away from the main line to curve back over it.

Turning round, this is the access ramp up on to the end of the embankment where the viaduct will start. After crossing the River Hiz underbridge, the new line will turn out on to this section of embankment that is being built up with brick rubble.  Pier number one will be situated just behind the wing wall on the left.

I then drove round to the end of Wilbury Way to check progress on the east side of the main line. This new "hill" has appeared in the former sewage treatment works since my last visit.  A similar heap of pile tops to the one on the other side can be seen to the right.

My last shot shows that work has started on the chalk removal on Wilbury Hill. The planning application is not being heard by the county council planning committee until next week so they must be pretty confident that permission will be granted.  From this distance, it looks like they are removing the top soil ready to start quarrying the chalk.

Work continues apace part three

Just to complete the picture, I ventured out along the footpath beside the Cambridge branch.  The permanent way trains had gone and service trains were operating again.  I walked as far as the new fence blocking the public footpath.  No signs of explanation, just blocked off.

I took this just after clearing the factories and shows the stripped ground where the embankment will be constructed.  The water tanker can be seen in a number of previous pictures.

 The start of the building of the occupation bridge.  This is extent of the topsoil removal.  In the background you can see the test boring on Wilbury Hill.  The Icknield Way is the hedge line just below it.

 New bridge from another angle.  Chalk is being piled up here already.  Although you can't see it, a medium voltage cable has been buried since my last visit. The pylon is just right of centre and the next one is immediately to my left.

 Finally the point where the two embankments will meet.  Nothing has changed here and the original blue pegs marking the centre line of the new embankment are still in place.

Work continues apace part two

Today I went along the Stotfold Road to the top of Wilbury Hill where the Icknield Way emerges before passing through Letchworth.  I walked along it westwards almost as far as the main line.  I took some shots from a different perspective.  To the right (north) of the Icknield Way you could see that the field had been pegged out for the chalk extraction.  There was a public notice stating that Network Rail had applied for planning permission to quarry chalk and that any submissions had to be received by 21st May.  This means that work can't start until at least the end of May making the proposed timescales very tight.   This must have been a very late change of plan because the field was planted with wheat.  This will make the removal of the top soil more difficult.  It would surely have been easier to do when the field had been ploughed.  I am guessing that the farmer will be fairly compensated for the loss of his or her crop.

First shot from the top of the hill looks towards the main line.  Top centre you can make out the pile drivers and cranes.  The route of the new line passes to the left just below the factories.

Here is evidence of the test boring

 Looking down on the work site.  Two very long permanent way trains were parked on the branch the whole time I was there. Rail replacement bus joy for some people I guess!

This is the access "road" to Wilbury Hill from the site

 Work has also started on the farmer's accommodation underbridge.  The field between the two embankments would have been completely cut off.  There was also talk of it being used for access to the industrial area as currently the only way in is through residential areas constrained by the low arch railway bridge in Woolgrove Road.

 Looking back at Wilbury Hill with the test boring in evidence.  It will be interesting to compare this photo to one when the chalk removal has been completed.

Returning down the Stotfold Road a shot of the work site.

Work continues apace part one

Despite the continuing bad weather, work on the project has stepped up a gear.  Piling work continued until quite late into the evening, maybe to catch up on lost time when the weather was too bad to operate.   Stripping of the route of the embankment has also continued.  Network Rail has applied to quarry chalk locally which will apparently save 22,000 lorry movements.  Naturally this has delighted the residents of the Wilbury Hills area who are understandably concerned about the high number of large lorries passing through on their way to the site.  However this has angered environmentalists and countryside groups who do not want the local landscape ruined by quarrying.  There are also a number of ancient burial barrows in the area.  Network Rail want to quarry chalk from Wilbury Hill to the north of the future embankment adjacent to the main work site.  They say that they will reinstate the hillside after the work is completed.  The timescale for the work to be completed is end of August for the embankment and 7th September for the land re-instatement.  This seems like an ambitious timescale but we will soon see if this is the case or not.  For those interested the details of the work can be found here:-

http://www.north-herts.gov.uk/docfilesrv/1/00/97/52/00975242.pdf

I was able to make a brief visit to the west side of the main line today and took a few pictures.  I noticed yesterday test boring of  Wilbury Hill has started so weather permitting I will take a closer look over that side.

 First picture shows the pile driver now working on the lower level.  It appears as if the piles have been completed on the upper level.

 Moving up onto the higher level I took this shot looking back south.

 Another shot further up.  It is hard to make out but centre left you can just make out a group of recently poured piles.

 Moving north along the former Bedford line embankment, you can see the formwork being built up on what will be a viaduct support column.

  Looking over the main line to the other side , you can see in front of the crane another one being. constructed.   After a slow start, construction of the viaduct seems to picking up speed now.

There was a fair bit of activity on the site today and there was a group of workmen over by the hoarding.  Not sure exactly what they were doing but there was a digger loading dumper trucks on the lower level which were bring material up on to the higher ground.  There is another heap of concrete tops from the poured piles.  To the right, the extensive network of water pipes has been dismantled and stacked up.  This is also evidence that the pile driving is finished here.