Tridley Point Traditional Cache
-
Difficulty:
-
-
Terrain:
-
Size: 
(small)
Please note Use of geocaching.com services is subject to the terms and conditions
in our disclaimer.
Fairly level walk that uses some of the Cumbria Coastal Way. One of a series of 'point caches' around the Leven Estuary including Chapel Island.
A short walk from Canal Foot either along the shore or over the sands if you prefer (and the tide is out!).
The Cache is 16 miles and 69 chains from Carnforth, where the Furness Railway branches off from the LNWR main line that runs between London, Carlisle and Scotland.
The remains of the original Plate Layers Cottages can still be seen as can a modern wind speed detector at the side of the track (see Tridley Point Disaster (Nearly)
(For the benefit of those of you brought up with decimal measurements, there are 10 chains in a furlong and 8 furlongs in a mile. A cricket pitch - the distance between the wickets - is one chain in length, and a "strip" - an individual's allocation of part of a field in a medaieval open-field farming sytem - was said to be one chain wide by one furlong in length – hope that helps !)
The Viaduct was designed by Thomas Brunlee for the Ulverston and Lancaster Railway Company . He was considered to be the foremost engineer of iron bridges in his day.
An Act of Parliament of 1851 gave the company the necessary powers to construct a line from Ulverston to the LNWR's line at Carnforth and work began in 1853.
Much of the expense of building the railway went into the building of the two viaducts over the rivers at the head of Morecambe Bay.
The Leven Viaduct near Ulverston is the longest at just about 600 yards. It consists of 49 spans of which 48 vary in width between 7 metres and 12 metres but span 37 is by far the longest, at about 20 metres.
The reason for this is that it was designed to be opened in the manner of a drawbridge to allow ships to pass underneath, this was a pre-requisit demanded by th admiralty so as not to impede navigation to the port of Greenod. Later once the railway branch line to Lakeside, through Greenod was built the lifting span was sealed. Interestingly during a major upgrade programme in 2006 the lifting mechanism was examined but how it operated remained a mystery.
The major difficulty that Brunlees had during construction was in sinking the piles into the river bed. There was a great depth of sand that no ordinary pile driving technique could penetrate. Brunlees developed the system of water-blasting the sand out of the way. Into the resultant holes he sank tubular cast-iron cylinders with a large disc base. This process was repeated until the cylinders were sufficiently deep and they were then filled with concrete.
In its exposed position deterioration of the viaduct was however, quick to take effect and between 1885 and 1887 the longitudinal lattice girders were replaced. But this was not the worst. An examination of the cast-iron columns less than 30 years later revealed that they were in a desperate condition.
Such was the importance of the Furness haematite mines and iron and steel industries that nothing must occur that would impede the flow of materials in support of the war effort so despite the war austerity programme that was in force, it was decided in 1915 to surround the columns with masonry and infill with concrete. Much of the deckwork was also replaced at this time.
In the 1950s despite the moratorium on major projects enforced upon British Rail by the pro-road transport British Government, further repairs were carried out on the viaduct and these secured the future of the line.
But by the turn of the 21st Century the viaduct had deteriorated again. By now there was a speed limit of 20mph in force and it was clear to almost everyone that the viaduct was on its last legs. A warning was issued that it would soon be declared unsafe, by which process the whole Furness Line would be obliged to close down.
In 2002 a full investigation of the viaduct was undertaken, which led in 2004 to the identification of a scheme for reconstruction which was put out to tender and on 26th March 2006 the line was temporarily closed to traffic as repairs began.
A new deck, weighing 3500 tonnes was installed and more than 2,000 square metres of masonry was repaired. Just 16 weeks later, the viaduct was reopened.
The original cost of the construction of the viaduct was said to be £18,604, which doesn't sound like very much, but assuming an average inflation rate of only 6% this equates to about £180m in todays money!
The repairs in 2006 cost in the region of £14 million.
Additional Hints
(Decrypt)
Nobhg bar zrger orybj gur gjb ynetr fnaqfgbar oybpxf
Treasures
You'll collect a digital Treasure from one of these collections when you find and log this geocache:
Loading Treasures