Follow Us on Twitter

Monday, 5 April 2010

Two Tunnels Route: a work in progress ...

Devonshire Tunnel loading bank
The excavation continues, and new for last week was the removal of some of the infill from the site. The contractors have laid a haul road right into the work site for this. About 40 lorry loads will go, leaving ... space to excavate some more stuff from the filled cutting. That 'Stuff' has turned out to be as indicated in the test borehole - clean subsoil, pretty heavy and 'Clayey'. Some of it, at a pinch, you could probably throw and fire to make small pots (The site's not a million miles from the location of Oldfield Park's Victoria brickworks too)

Devonshire Tunnel
We've now heard from one of the people who filled the cutting here in the seventies. Apparently, the length between the tunnel and the entrance to the public open space was filled with earthy material from the embankments, the length down to Maple Grove bridge with rubbly stuff from the demolished bridges themselves - hence a largish panel of brickwork that can be seen, flat in the ground to one side of the Linear Park path, not far from the overbridge itself.

This stage of the excavation has lowered the ground level sufficiently that the tunnel portal is now visible to passers by from Linear Park itself.

Devonshire Tunnel from Maple Grove Bridge
This week may also have answered the important question of whether any part of the portal will be visible to someone standing on Maple Grove Bridge. The photo on the left is actually taken from the bridge, and shows that it appears that this will be the case. We're pleased at this: the bridge itself has survived to be a touchstone to the past - generations of people would stand there to watch trains climbing the bank before vanishing into the improbably small mouth of the tunnel itself - some can remember that sight to this day, so it's good to bring this old sightline back into being.

Devonshire Tunnel excavation from above
The weather's not been too unkind, the snows of mid-week stayed in mid-Wales, but there have been a few heavy downpours, and on Friday the excavation was somewhat running with water and had almost managed to accumulate a puddle in the bottom.

When viewed from above, there's an impression of the amount of material that has been removed in the current week. This is a good vantage point for an overview of the work, though it's quite difficult to judge the depth of the excavation. The plan calls for a slope down to the tunnel that's a maximum of one in twenty - any steeper, and it would not be so suitable for anyone who happens to be in a wheelchair - and the 'New' Linear Park will be rather more accessible than the present one - any access ramps following the same 'Ruling gradient' if at all possible.

One resident who has lived in the area for a good many years confirmed the fact that trains in the tunnel very much made their presence felt in the houses above the entire length of it - the ground seems to have been particularly good at carrying the vibration, with the passage of locos, night and day, announced by a low and half-felt rumble, while mantlepiece ornaments tended to need to be stuck down to avoid them walking off the edge and into the hearth.

Looking into Linear Park from above Devonshire Tunnel
You can see that the view along Linear Park itself has somewhat opened out. Research indicates that bats actually appreciate a certain amount of structure in the landscape, as it allows them to navigate more easily. Another need is of course insects, and it will be good if Linear Park continues to be managed to provide habitats that encourage insects (though not to the extent that it becomes a swamp!).

Maple Grove Bridge, in the distance, is actually a three arched structure, and is in good condition - it's well built and has received a waterproof deck and maintenance when needed from the local authority.

Devonshire Tunnel south portal While this work goes on,  the other, now less-regarded portal, at the far end of Devonshire Tunnel awaits its own rather less intensive restoration. For various reasons the entrance is a bit of a swamp, but it's already seen a little activity, in that the contractors have been through from this end to place tell-tales at the northern end of the tunnel to check that the present work isn't causing unmonitored movement. And of course the tunnel itself has been the subject of regular inspections from its owners, the British Railways Board (Residuary). In the image, to the right of the tunnel, copious amounts of wild garlic. The Two Tunnels route is a vampire-free area - and from a historical perspective, there's a tradition that the wild garlic that grows profusely around Bath is a gift from the Romans ...

Work party, Lyncombe Vale, March 15th 2008
The entire length in Lyncombe Vale makes for a good explore, it's still showing the benefits of the Two Tunnels group's 'Litter pick and clearance' work party there one wet March day in 2008. For some years an overgrowth of saplings was threatening to forever close the deep summit cutting beneath Moger's bridge. Since the volunteer day, other smaller scale work (not by us) has ensured that the stretch has stayed reasonably clean and clear. Here's an image from the day that shows a great deal of small stuff on the deck (and if you happened to be there, thanks again!)


Matthew Holbrook said...

Thanks for the detailed update Mark. Hope & Clay are doing a great job and they appear to have the perfect company name for the task in hand!

Rob said...

Thanks for the updates. I have some questions....

You mention "with rubbly stuff from the demolished bridges". What demolished bridges?

Is there an overall scheme in place for the entire job? What happens after the Devonshire cutting is cleared?

Why was the cutting filled in? The other three tunnel entrances were just locked closed... why is this one different?

John Yeo said...

Rob, your questions answered: The two bridges referred to were at Monksdale Road and Dartmouth Avenue,just a little further up the line in Oldfield Park. Both were demolished when the 'Linear Park' project was established in 1973. This was supposed to transform the disused railway line from abandoned formation to recreational park. Although heralded at the time, it was never a roaring success - never particularly well looked after or promoted and always an ugly duckling compared to Bath's other prestine parks. Removal of the bridges aided traffic flow and obviously negated British Railways Board and/or Bath City Council from liability for their upkeep. The spoil from these and the embankments abutting them was dumped in Devonshire cutting (where ironically it probably came from in the first place when the cutting was originally dug out in the early 1870s). Filling the cutting in and blocking off access to Devonshire Tunnel solved two problems: What to do with the spoil and how to negate safety fears regarding the tunnel. As regards your reference to an 'overall scheme' - just read this website or talk to Sustrans or the steering group who have done such a fantastically committed and commendable job in driving this project forward. Frank, Nigel, Mark, Matt, Lindsey, Gitte and the rest deserve medals and the highest praise for what they have achieved here. The ugly ducking is being transformed into a beautiful swan before our eyes.

Mark A said...

@Rob: Bath's library holds a couple of documents from the time Linear Park was planned.

One of the two goes into some detail on proposed designs for different parts of Linear Park, including a proposal that Devonshire Tunnel's cutting might house a collection of ratilway memorabilia and that the tunnel be sealed a few feet inside the portal, so that the remaining length would provide a wet weather shelter.

In the event, Linear Park being built in 1973, this was a time of great economic uncertainty which materialised in the form of rapid inflation in the price of oil. Most of the work to create the park emerged as simple 'Earth moving and demolition', the money ran out before the restorative work, resulting in a 'Rough and ready' appearance to things.

As an emergency remedy for its barrenness, residents tell us that the filled Devonshire Tunnel cutting actually received a top dressing of 'Something fragrant from Saltford', and they have told us that the resulting crop of tomatoes had to be seen to be believed!

As John Yeo says, in the event the tunnel was simply buried to put it out of mind - and while an amenity of sorts was created from the line, owing to the economic crisis, the parks department battled for many years to improve Linear Park (and it has to be said that by 2004 it was not even easy to walk along the bit north of Dartmouth Avenue as the undergrowth was taking over)

With Linear Park 'Complete' there was no further funding to work on the Lyncombe Vale section, and in any case the resources and values weren't available to think of joining the three separate sections of council owned route - at that time, old tunnels and industrial history wasn't exactly at the top of the list when people considered visitor attractions, and the intention was to not take on avoidable maintenance liabilities, so British Rail were left to continue with the regular engineering inspections on the now buried tunnel - and on the bridge across the GW line.

Despite this (in some ways) debacle, the city council at that time are to be thanked that they had the foresight to create anything from the old line - the alternative being that various parts were proposed for use as a road (Bellotts Road to Dartmouth Avenue) or to provide housing and extend an industrial estate (around Monksdale Road). Neither of those proposals went ahead, so Bath's been gifted a Linear Park that is reasonably continuous.

So it happens that the Lyncombe Vale portals have not received the 'Burial treatment' and as for Combe Down Tunnel, it wasn't actually sealed until the early 1980s - it seems that half of the population of Bath of a certain age remembers a trip through the tunnel as a regular Sunday afternoon jaunt.

Unfortunately a minority, regarding the line as a ruin, vandalised Tucking Mill Viaduct, so its deck was (eventually) blocked off. (One of said vandals has actually been in touch with the Two Tunnels group to apologise for his actions all those years ago)

And as for an overall scheme, indeed there is. To deliver the Two Tunnels route, Sustrans appointed a full time project manager with engineering experience back in April 2008.

While we've not (yet) put the project plan on the Two Tunnels web site, said plan indicates an eighteen month construction phase from March 2010. Once the excavation work at Devonshire Tunnel is complete, a bit of a hiatus is intended, then I believe the next task will be work to the rest of Linear Park. Of course, that work will not be on anything like the scale of that needed at Devonshire Tunnel.

Hope this answers your questions.

Rob said...

John, Mark - many thanks for both your responses. They've certainly answered my queries (though I may come up with some more in the future).

I'd like to add that the people who have been working to make this plan a reality certainly deserve massive congratulations and thanks. Perhaps a plaque somewhere along the route listing names? (How long has it been since the idea was first.... ermmm.... idead?)

Apologies if this appears twice... having some problems posting messages.

Stanno said...

Hi Frank.
Roz and I were at the Devonshire Tunnel Saturday after our two mile walk , We could see a great improvment there and not to much mud, Now that is some thing lol.
Hope and Clay are doing a great job
well done ,All the best to you and the team.