Longest, Highest, Deepest

Today was meant to start gently with a potter to the shop for bread and then the short cruise to our appointment.  Instead, my phone rang before I was ready to get out of bed: “Is that the good ship Bartimaeus?”, “Are you here?”.  I agreed to get to the rendezvous as soon as we could.  We were both dressed and cast off in record time, coffee could be drunk on the move.  We had less than half a mile to go…

Clare suggested I might have misread or misunderstood the email.  “Did you book the wrong way?”  I found the email, it confirmed what I had remembered, we were supposedly due at 11.30 to take the Standedge Tunnel from Marsden to Diggle.  The friendly folk at tunnel control were relaxed about it though – it isn’t them who send the emails.

During the short journey, we had started to get unusual behaviour from the hybrid system.  For a few weeks now there has been an occasional clattering noise under certain conditions.  Usually it resolves with a slight change in engine speed.  This morning it was much worse and then stopped.  Afterwards the system complained of “clutch slip” and wouldn’t generate electricity.  While we were waiting for various things to happen I had a quick look in the engine bay.  I wasn’t surprised to see the broken drive belt – we seem to go through them at a rate of about one per year.

I’d hoped to drive through the tunnel on electric, that would require a drive belt!  There are two spare belts threaded on to the propellor shaft.  I replaced one last year in about ten minutes, so I set about a repeat performance.  It was as easy as I had remembered, but it did take up the time I might have otherwise used to grab some breakfast.

Trevor was to be our pilot for the trip and Alastair was going to shadow us using a vehicle in the safety tunnel.  He’d set off by road soon after we arrived so he could drive the length of the tunnel from the other end before we started.  We were kitted out with hard hats and fluorescent jackets and advised to wear waterproofs and life jackets.

Clare was advised to sit up front and enjoy the ride, while Trevor sat at the back to give me guidance and other information.  Our tunnel light had been augmented by a light at the front and on the rear hatch, so the tunnel sides in front and above the boat were well lit.  I didn’t need Trevor to point out the sudden drop in height a few boat lengths in.

Canal tunnel.  The walls of a canal tunnel are made of dressed stone.  A short distance ahead of the boat the profile changes abruptly to be much lower.
Dressed Stone Tunnel Walls

As well as abrupt changes in profile, the tunnel walls changed from one material to another.  Some sections were entirely composed of bedrock.  Grooves in the surface were the remains of holes drilled in to the rock to insert explosives.

Rock walls.  The walls  of a canal tunnel are cut from the bedrock.  There are grooves in the surface which are the remains of the drilled holes used to insert explosives.  The roof is irregular and a change of profile is visible ahead.
Tunnel Wall Blasted Out of Bedrock

Trevor had warned me that there were a few places where the tunnel is very wet, mostly at the end we were starting from.  We could hear the water before we could see it, but there was no way we were going to avoid it.  This was the bottom of the shaft we’d seen yesterday.  If I hadn’t been dressed for this it would have been miserable, but I was standing in a waterproof coat and hard hat, so I didn’t even feel it.  There were a few more wet points like this, but the vast majority of the tunnel was not even drippy.

Water curtain.  A curtain of water partially obscures the view of the canal tunnel ahead.  The walls are tinged with an orange deposit which has been left by the water over the centuries.
Water Curtain Below a Ventilation Shaft

A recent innovation in the tunnel is a communication system.  The equipment for this has been hung in the centre of the tunnel at intervals.  They are not the lowest thing in the tunnel by any means but they were all central and low enough that I had to dodge them.  The obvious step to the port side left me at risk of catching the cable, which surely could have been clipped a little higher.  Trevor discovered that his hand held radio could not get a signal even directly under the first of these.

Tunnel alien.  An electronic contraption hangs beneath a metal beam that crosses a canal tunnel.  The equipment has aerials facing along the tunnel and other features to either side.  A cable runs under the beam to the side of the canal.
Alien Creature in the Tunnel

This tunnel is the the highest section of canal in the UK at 645 feet above sea level.  In the middle, it is also the deepest underground at 639 feet.  At a little over 3 miles long, it is the longest canal tunnel in the UK, and the longest canal tunnel in use in the world.  Some sections have been repaired and reinforced with spray concrete.  This was sometimes particularly hard to navigate as the featureless surface hides the deformations.  Marks made by previous boats losing their paint were useful guides for me.

Concrete foam.  The walls of  a canal tunnel have been reinforced with spray concrete.  The resulting smoothed shape looks like something from a film set.
Tunnel Walls Coated in Spray Concrete

Three railway tunnels run parallel to the canal through the hill. The canal was bought by the railway company and used to help with the building of their tunnels. The tunnels are connected by adits – side passages. The spoil from tunnelling was brought through the adits and taken away by barge. In some sections, the new tunnels affected the canal tunnel, so brick reinforcing arches have been built. The arches are not neatly aligned and in some places made it tricky to see which way the tunnel was turning.

Criss cross.  Reinforcing brick arches criss cross over the roof of the canal tunnel.  The arches are offset from each other creating an intricate and confusing pattern ahead.
Reinforcing Arches Criss Cross Ahead

Alistair was waiting for us to pass at the end of a number of the adits. He was driving through a former railway tunnel. to get ahead of us. At one of these he handed Trevor another radio – that one seemed to work.

Every so often we could feel a strong draft, and then the sound of a train passing through the newest of the tunnels (built in 1894).  Sometimes the pressure change would cause mist to fill the tunnel.  The effect only lasted a few seconds but was a little disconcerting.  Apparently on humid summer days it can be even more dramatic.

We were travelling through at a very sedate pace. It was an hour and a half before we could see the light at the end of the tunnel, and another half an hour before we reached it.

Rock wall.  The walls of a canal tunnel are made of rough bedrock with some concrete sprayed in places to stabilise it.  The light at the end of the tunnel is visible.
Light at the End of the Tunnel

The tunnel is slightly longer at both ends than when it was first built.  The double track railway tunnel was dug on the opposite side of the canal from the previous two.  The tracks run above and nearly parallel to the canal, lengthening the tunnel by 242 yards at the Diggle end.

Tunnel extension.  The end of the tunnel has been extended to allow a railway line to run above it.  The vertical walls here are made of dressed stone.  The roof is made fromhorizontal cast iron girders.
Canal Tunnel Extension for the Railway

About two hours after we went in, we emerged in to the sunshine.  We were now in Greater Manchester, though when the tunnel was first built this was part of Yorkshire.  We thanked Trevor and Alistair for their help.  They had some lunch before introducing themselves to the people on the boat waiting to go the other way.  They seem to spend a lot of time in the tunnel.  Trevor has written a book on the tunnels, I have purchased a signed copy which I shall read with interest.

Standedge Tunnel West Portal.  What appears to be a stone arch bridge is in fact the portal to the Standedge Canal Tunnel.  The entrance itself is blocked with ornate gates.  The design of the gates incorporates a narrowboat with legs extended as if to propel the boat through the tunnel.
Standedge Tunnel West Portal with Ornate Gates Showing A Boat Being Legged