Happenings at Tesco Tunnel
Gerrards Cross
2006
A part of Guy Gorton's website

After trains began to run again on August 20, 2005, the construction site was virtually shut down.  It was presumably inspected from time to time because various minor works appeared, such as improved drainage at the gap in the tunnel.  Some survey marks were attached here and there, probably to allow movement to be detected.

Click on a thumbnail to see a larger image.   You can go the TescoTunnel home page here.

3432

A forlorn sight on the station side of Packhorse Road Bridge, early February 2006.  In the picture are to be seen the conveyor belt, including the bridge over Station Approach in the distance and the tube taking it through the north arch of Packhorse Road Bridge.



 


3434

The Tesco shed itself, held up by rusting girders, is unchanged for six months, and the machine in the centre-rear has not moved over the same period.





3437


The main entrance, where the light structure is to the left of the main shed, should have been busy with customers last October.






3527


A drain has been put in on each side of the tracks to channel water to where it should be.  Otherwise, everything is as it was left..





  3568


Hardhats and high vis jackets began to appear again in late March 2006 when Costain took over the site from Jackson.  The first works seemed to be safety related - perhaps Costain operate different rules.  Here is a new fence right across the site and there were other new fences further from the camera.

 


3565

Meanwhile, Gerrards Cross put Tesco's shop out of its mind and celebrated the centenary of the opening of the railway on April 2, 1906 in great style.  Notables from Chiltern Railways were there and it was particularly pleasing to meet the grandson of the first Station Master of Gerrards Cross.  It was the coming of the railway that created modern Gerrards Cross so there was a big exhibition later in April covering many aspects of the first hundred years.




3540


Chiltern Railways entered ito the spirit of things with steam specials between Marylebone and High Wycombe, 48151 on the London end, Leander on the country end.

 



3591

The thought entered some people's head that this was really a test to see how the tunnel and its measuring instruments stood up to a good exhaust blast!  Here is 48151 accelerating through the tunnel gap.




Part way through April, a few things started happening on site.

 

0610
Back in January 2005 the huge crawler crane used the line of tunnel segment bases and a set of concrete slabs as its track.  Segments were delivered through the tunnel.  This is clearly not an option in the present situation.





1901

In early June 2005 the multi-wheeled crane was standing on raised ground and required a great width for its stabilising feet.  The segments were delivered on semi-trailers reversed down the slope behind them.  After the last segments were positioned and 2 of the 4 tunnel portal pieces were in place, the crane left by the same route.  I do not know what was intended for the placement of the final tunnel portal pieces,



 
3669

Small drilling rigs started making test bores all along the filled area, close to the tunnel segments but probably just clear of the foundations.  Presumably Costain need to check that the layers of fill material are where they should be.


 



sandbags

These are the two remaining parts of the eastern tunnel portal.  The top image was taken as part of a wider scene on 14 April, illustrating no change since August  The lower image was taken on 16 May showing how the ground has been shored up with sandbags, probably as a precaution against slippage of the cutting side which has been quite sharply cut away at this point..

 




3775

Surveying levels has been going on all over the site for some weeks now.  Here the surveying has entered the east end of the west tunnel where there is a tower and what looks like a permanent survey point - invisible to the naked eye from Marsham Lane bridge but a digital camera can just about bring it out.



conveyor


I do not know when it was taken away, but the last stage of the conveyor belt system is no longer there!  It was there on 14 April, it was not on 23 May, but I did not see it go.  The drive system at the destination end has gone too.  Probably an economy measure to save hire costs.


 



3754



The segment foundations in the collapse area are undergoing detailed inspection, a task that seems to need a lot of people.  From this distance, the groove in which the tunnel segments sit seems in good order.


 




3769



The southern side comes under close scrutiny and some measurement it seems.  The glimpse at the top of a tripod is of another surveying team.





If the project goes ahead, how will the tunnel segments be placed?


0610
Back in January 2005 the huge crawler crane used the line of tunnel segment bases and a set of concrete slabs as its track.  Segments were delivered through the tunnel.  This is clearly not an option in the present situation.





1901

In early June 2005 the multi-wheeled crane was standing on raised ground and required a great width for its stabilising feet.  The segments were delivered on semi-trailers reversed down the slope behind them.  After the last segments were positioned and 2 of the 4 tunnel portal pieces were in place, the crane left by the same route.  I do not know what was intended for the placement of the final tunnel portal pieces,



3781
May 2006.
The present situation near the tunnel gap is that the ground is built up, retained by a wooden wall as seen here.
  This is much higher than the level used by the wheeled crane last year.  The slope in the distance is also very steep.  An interesting factor is that surely the retaining wall will have to be removed, otherwise the necessary side pressure from fill material will not be present.  How will it be done?  Answers on a postcard to Costain.



You can go the TescoTunnel home page here.

Pictures and text Guy Gorton 2006
Page constrained to 1024 pix, no other changes, October 2014