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Monday 29 March 2010

Bath's Lost Underground Railway

Unseen since 1973, here it is at last. The contractors, Hope and Clay, have just a few feet to go now before they're down to the original level of the trackbed. Pleasingly, the excavation hasn't filled with water. As for the portal, it seems to have survived its burial rather well ...
Given the location, it's just about the most minimal structure possible. The same can't be said for the access shaft built when the cutting was filled - a supporter has suggested that this be retained and moved to a position opposite NCN 24's William Smith monument south of Midford where it can form a balancing counterpart.
Despite the minimalist design, it doesn't mean that the structure misses out on coping stones, or detailing. In the afternoon, the sun finds its way into the cutting. In the dark of the tunnel, the remains of plant fronds that once grew towards the light now wander in the darkness towards the block wall that sealed it. The wall stays for now, as the tunnel may have a few bats in it, and this is not yet a good time of year to disturb them.
It appears that the concrete block wall has not been 'Stuck' to the portal, making its removal rather more easy than if the contractors who filled the cutting had attached it more strongly. In fact they seem to have taken reasonable care to ensure the portal survived undamaged.

Sandbags act as markers for the contractors as they finish excavating the wing walls ... the cutting sides are already somewhat dressed with topsoil. In due course they'll be put to grass, cowslips and blue butterflies.
On the down side of the old line, the support wire for the signal post seen in this image emerges from the fill, one end anchored in the ground and the other perhaps still attached to the felled post. Behind the camera, the contractors still have much earth moving to do.

Friday 26 March 2010

Looks like this was some sort of transport system

Devonshire Tunnel portal excavation
The end of another working week. You'll see that Hope and Clay have been carefully plugging away to excavate the earth from in front of the structure. Their method has been to remove the load on the structure in an 'even handed' way, monitoring for movement as they go - tunnel portals can be sensitive, in that they sit at a junction between made ground and undisturbed material. Hence, they reward being treated appropriately.

The fill is now gone from the portal down to the level of the trackbed. Monitoring will now continue, as movement, if any, is likely to be gradual and occur over weeks in terms of time - and hopefully less than a smidge in extent. The portal, having shrugged off heavy vibration from passing trains for over ninety years, is not likely to be seriously troublesome. (There are several accounts from people who lived above this particular tunnel that mantlepiece ornaments had to be glued down ...)

Devonshire Tunnel portal excavation
The cylindrical structure is the access shaft built when the tunnel was sealed. At a later stage the original access was tending to bury itself, and the shaft had a bit of an extension added to its top - if you've visited the cutting you'll remember this, around four feet high and buried in brambles. The contractors have tidily removed the extension - they swiped it off in one piece with a bucket - Matt happened to be there at the time. After removing the extension they've put a new cover on the access shaft.

Devonshire Tunnel portal excavation
Both shaft and block wall stays put for the moment, as it's not yet a good time of year to alter the environment for the (very few if any) bats inside. Another aspect of the task is that topsoil and subsoil are treated separately, subsoil can then be reused where appropriate in the excavation and later covered with topsoil in which things will grow. The images show that some of the cutting sides are already dressed with topsoil - the final part of their treatment involves grassing them over, but the topsoil itself will also contain seeds from previous years growth and will provide continuity.

This unveiling is a bit like a birthday present for the project, after four years of anticipation. It's a present which is pretty well unwrapped now, but for the time being it's not easy to see and very much a work in progress - looking from the direction of Maple Grove bridge, the spoil heap's in the way.

There was a concern that they may have been damaged, but it looks as though the tunnel portal's wing walls - at either side - are going to be fine - the photos show a glimpse of the up side wall capped by its coping stones. Unlike our three other portals, this one seems to be 'As built'.

Lined up against the other architecture the city can provide, this structure is inconsequential. However, many of us find that it feels particularly good to have it back.

Wednesday 24 March 2010

Work continues at Devonshire Tunnel

Wed 24 Mar 10, and, despite the dreary weather, the Hope Clay diggers continue apace. Working in tandem, this YouTube video shows how one digger removes spoil from the tunnel portal and the other moves it back towards the spoil heap.

Thursday 18 March 2010

There's something in the pit ...

The contractors - Hope and Clay - have now dug an initial pit - with the intention of proving the location of the tunnel portal and also its condition - it was quite possible that the structure had been seriously damaged in the process of burying it.

However, a length of the capping stones to the portal itself are now in the light for the first time since the nineteen seventies, and it appears that the team that worked to fill the cutting all those years ago took good care not to damage it. This is thoroughly good news for the Two Tunnels project.

There could not be a greater contrast between this tunnel portal and that of Brunel's Box tunnel built some miles to the east and some forty years earlier but each tells its own tale and it will be good to have this one back. Please revisit the blog as we hope to have more photos online shortly.

If you intend to visit the works, please note that for the time being the tunnel portal will remain some way inside the safety fencing surrounding the works area. If you're on foot, the public road above the tunnel portal itself gives a good overview of the entire length between the tunnel portal and Maple Grove bridge.

On the subject of the contractors, we've the early impression that we're fortunate to have an experienced and well trained team working to shape the new entrance to Devonshire Tunnel on this as yet little recognised but landmark project for the city. Should you encounter or visit the works you can play a part in letting them know they're welcome - and making a not-straightforward job of excavating the tunnel portal without damage to it as easy as possible.

Wednesday 17 March 2010

Work restarts - Wed 17 Mar 10


Following a few days break while the Council licencing issue was sorted out, work has re-started to clear and excavate Devonshire Tunnel northern portal.

Friday 12 March 2010

Work Starts

Following the highly successful start of work celebration the previous day, on Tuesday 9 March 2010 the Hope and Clay contractors started work on excavating the Devonshire Tunnel. Unfortunately it stopped shortly afterwards due to the Council Parks Dept not having issued a license to work on Council land. It is hoped to re-start work on Monday 15 March 2010 or soon thereafter.

Monday 8 March 2010

3,2,1 and liftoff for the Two Tunnels Project!

We're pretty overwhelmed by the support shown this afternoon, people braving what turned out to be ... actually not too muddy and a glorious sunny day for good measure ... all there to witness the start of work on the Two Tunnels route.

A very impressive digger had been brought to the site by the contractors Hope and Clay, forming a backdrop to the ceremony. Nigel produced a smashing engraved ceremonial spade. The CE of Sustrans was along to help launch the start of work on the project - along with its engineer.

And many many many supporters arrived from all points of the compass. Brilliant!

For good measure, the photographer from the local paper - the Bath Chronicle - and then a film crew from BBC Points West too - we had a good couple of minutes on that - and also a mention on ITV local news as well. All good news for something that will improve Bath as a liveable city no end. We'll have more photos and hopefully some video on the web site very shortly.

Monday 1 March 2010

More stirrings: this time Linear Park

We didn't expect this. A litter pick organised by an Oldfield Park community group on a threateningly wet and chilly Sunday afternoon dragged improbable amounts of crap from the historic collection of litter between the Dartmouth Avenue and Monksdale Road bridge sites.

This would have been an unpleasant and expensive job for a three person council crew. Split between about thirty people armed with litter pickers the afternoon flew past.

The result: well,  you wouldn't say the section was clean enough to eat off, but it's certainly far more of a credit to the locality, and more wildlife friendly too. Some people say Oldfield Park is ugly. It's certainly not, and Linear Park offers all sorts of perspectives on the city, a tour of suburban Bath cuts to rooftop views of Georgian Crescents and then a close shave with one of the UK's finest italianate churches.