Lock 4 Marple - has it been moved?

[magpie patrick]

When bringing Lutine up Marple Locks on Thursday a very helpful friend of a friend assisted: he never set foot on the boat but worked the locks and cycled ahead to set each one. John (for that was his name) helps boats most weeks and knows the locks well.

 

He suggested that lock 4 (pictured below) was moved downstream when the railway was built in the 1860s, so that it wasn't over the railway tunnel under the canal, a theory I had never heard before

 

 

The railway passes under the canal in Marple (North) tunnel between locks 4 and 5, as can be seen in this view from Google Earth

 

 

The pound is also very wide between the two locks, and there is no doubt that lock 4 is very helpfully placed as if planned for the railway tunnel.

 

The only evidence presented on site is a number of large blocks next to the lock

 

 

They are large, but other than a slightly implausible argument that they were "left over" when the lock was moved no explanation was offered.

 

Argument for the move - lock 4 is located so well in relation to the tunnel it could have been planned, although clearly this could have been achieved by aligning the tunnel carefully rather than moving the lock

 

argument against - the pounds above and below lock 4 are almost exactly the same length at around 94 metres, if the lock had been moved one would expect a discrepency.

 

The canal was already owned by the railway company when the railway was built.

 

Thoughts anyone?

[Bloomsberry]

Hi

There is a virtual tour of Marple Locks here

http://www.marple-uk.com/locks/index.htm

There is a section on lock 4 which mentions the building of the tunnel underneath the canal but doesn't mention anything about the lock being moved.

The original site has obviously been oblliterated and lies under the canal anyway so there'll be no evidence of it's existence there. The blocks look very squarely shaped so don't think they are a natural feature and were shaped and transported there for a particular reason. Could be remains of the building of the current lock although it would appear wasteful.

Interesting subject..

[Pluto]

I have a copy of the 1889 survey for the canal which was based upon an earlier survey. Nothing suggests that lock 4 has been moved, but the canal at the bottom does seem to have been altered for some reason.

[Guest]

Out of interest why would it be moved anyway for the building of a tunnel?

[magpie patrick]

Out of interest why would it be moved anyway for the building of a tunnel?

each lock is a drop of over 13 feet: I haven't checked but knowing the area I would imagine the canal level below lock 4 (and thus the level of the floor of lock 4) isn't high enough for the railway tunnel to be built under it.

 

Of course this is also a reason for putting the railway tunnel above lock 4, rather than moving lock 4 to below the railway tunnel...

[Paul G2]

About those big blocks...

 

Take a look at these blocks:

 

They are from an article titled:

 

Tunnel Repairs - 1982, Part II , Blisworth, Northamptonshire, UK.

 

 

Which can be found here: http://www.blisworth.org.uk/images/tunneltwo-1982.htm

 

There are similarities between the old blocks the OP shows and the modern blocks used in the Blisworth Tunnel repairs. Perhaps those blocks are left over from building this railroad tunnel under the canal.

[magpie patrick]

About those big blocks...

 

There are similarities between the old blocks the OP shows and the modern blocks used in the Blisworth Tunnel repairs. Perhaps those blocks are left over from building this railroad tunnel under the canal.

Interesting observation - the blocks near Lock 4 are rather large (although I'll have to go back and see if they are larger than the ones used in lock 4) and not all squared - suggesting they weren't for a lock perhaps. I like the comparison

[Guest]

Out of interest why would it be moved anyway for the building of a tunnel?

Of course logical, I hadn't appreciated the level of the fall on that lock.

 

Cheers.

[Heartland]

Looking at the 1889 map Mike posted which shows the Bridge 27 (for the Great Central & Midland Joint Railway crossing over the canal) as well as the siding to the canal interchange wharf, is there a copy of the next sheet which shows the tunnel?

 

Ray Shill

[Athy]

Is this the only example of a railway tunnel under a canal?

[Pluto]

The survey showing lock 4 does not add anything material. On railway tunnels under canals, there are several under the L&LC in Liverpool, mainly goods lines, but there was also the passenger line down to Princes Dock Station which served the trans-Atlantic, Irish and IOM services.

[furnessvale]

Is this the only example of a railway tunnel under a canal?

There is another one on the same canal.

 

The former Midland Railway line from Manchester Central to St Pancras goes through Disley tunnel under the Upper Peak Forest Canal and the same tunnel then goes under the Macclesfield Canal before emerging.

 

George ex nb Alton retired

[davidg]

Is this the only example of a railway tunnel under a canal?

 

 

Also one under the Chester Canal at the bottom end of the Christleton pound.

[furnessvale]

There is another one on the same canal.

 

The former Midland Railway line from Manchester Central to St Pancras goes through Disley tunnel under the Upper Peak Forest Canal and the same tunnel then goes under the Macclesfield Canal before emerging.

 

George ex nb Alton retired

 

Edited to add.

 

This poses another question. Are there any other railway tunnels passing under more than one canal and if so what is the maximum number?

 

Perhaps something on the BCN?

[davidg]

The Stour Valley goes under the top of the 13 & the Birmingham Suburban (New St - Five Ways) goes under the W&B just before Salvage Turn.

[furnessvale]

When bringing Lutine up Marple Locks on Thursday a very helpful friend of a friend assisted: he never set foot on the boat but worked the locks and cycled ahead to set each one. John (for that was his name) helps boats most weeks and knows the locks well.

 

He suggested that lock 4 (pictured below) was moved downstream when the railway was built in the 1860s, so that it wasn't over the railway tunnel under the canal, a theory I had never heard before

 

 

The railway passes under the canal in Marple (North) tunnel between locks 4 and 5, as can be seen in this view from Google Earth

 

 

The pound is also very wide between the two locks, and there is no doubt that lock 4 is very helpfully placed as if planned for the railway tunnel.

 

The only evidence presented on site is a number of large blocks next to the lock

 

 

They are large, but other than a slightly implausible argument that they were "left over" when the lock was moved no explanation was offered.

 

Argument for the move - lock 4 is located so well in relation to the tunnel it could have been planned, although clearly this could have been achieved by aligning the tunnel carefully rather than moving the lock

 

argument against - the pounds above and below lock 4 are almost exactly the same length at around 94 metres, if the lock had been moved one would expect a discrepency.

 

The canal was already owned by the railway company when the railway was built.

 

Thoughts anyone?

A possible argument for.

 

Whilst the pound lengths are similar the width is quite different. Thus lock 4 could have started out further south and the available volume of water in each pound would be similar.

 

George ex nb Alton retired

[magpie patrick]

There is another one on the same canal.

 

The former Midland Railway line from Manchester Central to St Pancras goes through Disley tunnel under the Upper Peak Forest Canal and the same tunnel then goes under the Macclesfield Canal before emerging.

 

George ex nb Alton retired

 

Indeed, Lutine's current mooring is over Disley Tunnel on the Macclesfield, the owner of the house has a double width plot becauase no house was built over the tunnel.

 

On the general question, the answer is plenty of railway tunnels go under canals, but it is probable that Marple North Tunnel (the one under the canal between locks 4 and 5 at Marple) only exists because of the canal, the railway is in cutting generally in that area. Elsewhere the tunnels were either quite a bit meatier (Disley for example) or were aqueducts.

Edited August 17, 2014 by magpie patrick

[furnessvale]

 

Indeed, Lutine's current mooring is over Disley Tunnel on the Macclesfield, the owner of the house has a double width plot becauase no house was built over the tunnel.

 

On the general question, the answer is plenty of railway tunnels go under canals, but it is probable that Marple North Tunnel (the one under the canal between locks 4 and 5 at Marple) only exists because of the canal, the railway is in cutting generally in that area. Elsewhere the tunnels were either quite a bit meatier (Disley for example) or were aqueducts.

Thanks for that. It prompted me to look at Google maps satellite view. This shows a distinct line of greenery along the line of the tunnel where building has been avoided, a fact I had not considered before.

 

As an old mate of mine used to say, "never a day goes by 'bout you don't learn summat".

 

George ex nb Alton retired

[Señor Chris]

 

it is probable that Marple North Tunnel (the one under the canal between locks 4 and 5 at Marple) only exists because of the canal, the railway is in cutting generally in that area

 

If you were having to dig a cutting anyway, you would surely do it so as not to disrupt the canal ?

 

Is it possible the lock was moved after the tunnel was built if it was causing problems ?

[magpie patrick]

A possible argument for.

 

Whilst the pound lengths are similar the width is quite different. Thus lock 4 could have started out further south and the available volume of water in each pound would be similar.

 

George ex nb Alton retired

 

Yes, I'd pondered that, it is very wide. Marple Lock pounds are a right mix in this respect

 

 

 

If you were having to dig a cutting anyway, you would surely do it so as not to disrupt the canal ?

 

Is it possible the lock was moved after the tunnel was built if it was causing problems ?

 

Possible, but I suspect the floor of lock 4 is too low for the tunnel, they'd have found the problem very quickly. Certianly the course of the railway is very clealy planned to be above lock 4, whether or not that required the lock to be moved

 

I've assumed the railway was tunneled under the canal on a length where the railway is otherwise in cutting, but it may have been cut and cover, which might also explain the very wide pound, with the canal being moved sideways as the railway was excavated and then covered over. The railway company owned the canal, and whilst they would not have wanted trade too heavily disrupted, they had some latitude to mess the canal about in this way ifb they wished.

 

I've nothing beyond the most circumstantial evidence that the lock was moved at all, it was suggested to me and seems plausible, but that doesn't make it true.

[Athy]

Fascinating subcanalian tunnel facts, thanks chaps. It's something which had never occurred to me before.

[Pluto]

This is the 4th lock area from the canal survey which shows the pounds to be fairly equal in length. Of course, the two lower ones could have been wider and may have been reduced when the railway was built. The survey does show a railway/canal transhipment wharf above the 2nd lock, the construction of which could have altered the volume of that pound. The railway's engineer would have had to balance the amount of cutting required with finding a level suitable to get under the canal. He would not have gone to the expense of moving a lock if he could find a suitable line which, to me, he seems to have done here. The tunnel would have been expense enough.

 

[Laurence Hogg]

Is this the only example of a railway tunnel under a canal?

Old turn junction in Birmingham is on top of the Stour Valley rail line out of New st, only 13ft from canal bed to tunnel lining!

[MoominPapa]

Don't forget that the lines from Kings Cross Station all pass through Gas Works tunnels, over which passes the Regent's Canal.

 

MP.

Edited August 17, 2014 by MoominPapa

[nicknorman]

Old turn junction in Birmingham is on top of the Stour Valley rail line out of New st, only 13ft from canal bed to tunnel lining!

And as I understand it (I'm sure you will correct me if I am wrong!), the "traffic island" at old turn junction is in fact a (now disused) ventilation shaft for the railway tunnel. If so, must surely be the only railway ventilation shaft emerging in the middle of a canal, in the UK?

Edited August 17, 2014 by nicknorman