2005 Gerrards Cross tunnel collapse

[Signal Head]

I've just come across this page (New Civil Engineer) with information concerning the final HSE report on the collapse of the 'Tesco Tunnel' in 2005 which some may remember. It was big news at the time, and it was most fortunate that there wasn't a train inside the structure when the collapse occurred. The article describes a catalogue of miscommunication, lack of communication and (to me) general incompetence and I thought it might be of interest to some on here.

It seems the report was never released, and in fact attempts to obtain it were repeatedly refused, which in itself is rather dubious. It is available now apparently thanks to one person's persistence via FOI requests.

 

[Railsigns]

Gareth Dennis has put a video on YouTube looking at the report in detail.

Why did the HSE not publish their original report? Well, thanks to an intrepid fan of the show, we've finally got hold of it! We'll be lawyering up as we flick through the pages of the draft report and stare in horror and the engineering negligence that nearly led to a multi-fatality rail disaster.

 

[150219]

I've just come across this page (New Civil Engineer) with information concerning the final HSE report on the collapse of the 'Tesco Tunnel' in 2005 which some may remember. It was big news at the time, and it was most fortunate that there wasn't a train inside the structure when the collapse occurred. The article describes a catalogue of miscommunication, lack of communication and (to me) general incompetence and I thought it might be of interest to some on here.

It seems the report was never released, and in fact attempts to obtain it were repeatedly refused, which in itself is rather dubious. It is available now apparently thanks to one person's persistence via FOI requests.

It was a close run thing. There was a London-bound train standing in the up platform at Gerrards Cross and a down train between Denham Golf Club and Gerrards Cross at the time it collapsed.

 

[crablab]

The report is available here: https://www.railwaysarchive.co.uk/docsummary.php?docID=7382

I don't know if the credit refers to @ainsworth74 or not!

 

[edwin_m]

This article on HS2 green tunnels emphasises how the covering over is co-ordinated to avoid a similar collapse.

HS2’s innovative green tunnels - Rail Engineer

Eiffage Kier Ferrovial Bam joint venture (EKFB) is delivering civil engineering works across an 80km section of HS2, between the Chiltern Tunnel and Long Itchington Wood. In June last year, EKFB and its French engineering specialist, Matière, began the construction of an innovative 2.5km-long...

www.railengineer.co.uk

Backfilling to each side and above the tunnel is carried out to a tightly controlled sequence, including a ‘permit to backfill’ process. This avoids possible unequal loading which could deform or damage the structure. Backfill material is placed and compacted in 250mm layers using selected arisings from the tunnel excavation or from nearby.

 

[satisnek]

Remember it well. In the aftermath Chiltern Railways offered a 50% fares discount so I had at least two cheap London trips even though they did involve a lengthy detour via Aylesbury. At the time it was said that a train had just passed through before the collapse, implying that the train precipitated it.

 

[edwin_m]

At the time it was said that a train had just passed through before the collapse, implying that the train precipitated it.

Possible that the vibrations from a train finally brought it down, but it would have had to be highly unstable for that to trigger it. So it doesn't remove the responsibility from the teams that created the instability by messing up with the earth covering.

 

[satisnek]

Possible that the vibrations from a train finally brought it down, but it would have had to be highly unstable for that to trigger it. So it doesn't remove the responsibility from the teams that created the instability by messing up with the earth covering.

Most definitely. Trains don't normally leave collapsed overline structures in their wake.

 

[Pigeon]

The report is available here: http://www.railwaysarchive.co.uk/docsummary.php?docID=7382

Thanks for that.

I always assumed it had been Tesco who had come up with the idea in the first place because who else would it be. I didn't realise until I read that report that it was Railtrack, of all people, who came up with it, and then touted it round until they found some sucker who would bite.

I guess this wasn't generally known at the time either, because the wikipedia article on the tunnel quotes the leader of South Bucks council as saying, after the collapse, "We want to know why such a hugely complex engineering process has been deemed necessary to build a relatively small new Tesco store". It would surely have strengthened the protesters' position considerably if they had known that the answer was "it wasn't".

 

[Bald Rick]

“You Shop, we Drop”

 

[Thebaz]

My word... As a chartered geospatial engineer with responsibilities for monitoring structures, I can't believe what I just read. To be consistently reporting large (and growing) deflections that were simply ignored by the project management is just.... it's just... No words. It's criminal, that's what it is. A total miracle no-one was killed or injured.