The Macclesfield Canal
The Macclesfield Canal was one of the last narrow canals to be built, indeed, it was very nearly built as a railway! A variety of ideas were proposed and the present canal was approved by Act of Parliament in April 1826. The route of the canal was surveyed by Thomas Telford and construction was engineered by William Crosley. The completed canal was opened on 9th November 1831 at a cost of £320,000.
The route takes the canal from Marple Junction with the Peak Forest Canal in the north 26¼ miles to the stop lock at Hall Green near Kidsgrove passing along the side of the most westerly Pennine hills through High Lane, Higher Poynton, Bollington, Macclesfield and Congleton, all in Cheshire, and Kidsgrove in Staffordshire in the south. Nowadays we normally regard the last 1½ miles to Harding's Wood Junction with the Trent & Mersey Canal as a part of the Macclesfield Canal although it was built as a branch of the T&MC.
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The Bridge
This Macclesfield Canal
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has full information about the bridge...
"Royal Oak swivel bridge no.49 was one of 13 originally built across the canal. Most were famers' accommodation bridges, joining divided fields in the same ownership. Royal Oak was the only swivel bridge to carry a public highway, and still does. The bridge has had at least three incarnations. What we believe to have been the original deck served for c.145 years and required replacement in 1973. We have many pictures of the works taken at this time showing the construction of the original bridge (above) and the new bridge, and also the progress of the work.
Notes very kindly submitted by John Powell, retired British Waterways Bridge Engineer.
The casting [top right] for the Royal Oak Swing Bridge No.49 is massive compared with the original drawing for Bridge No.47, I presume problems with strength had been experienced at some time in the past and measures taken to improve matters?
The picture [centre right] shows the Cast Iron King Post with wheel which would have been as originally built, the chain going over the wheel on the original drawing for Bridge No.47 is only about 6 inches long, so it is in all probabilty there, but difficult to see on the photograph.
The 1973 reconstruction of Royal Oak was undertaken by R.J. Russell & Co. Ltd., Civil Engineering Contractors, for the sum of £13,461.00 and I can confirm that the pintle shown in your photograph [bottom right] is the standard BW pintle being used at that time. It had been improved over the old cannon ball pintle [top right] by the incorporation of the vertical post which sits between two transverse beams with a collar assembly fixing the post firmly to the deck.
The vertical post can now transfer any horizontal forces from either traffic braking on the deck or boats hitting the side of the bridge, when previously these forces could only be taken by friction and resulted in deck movement.
Unfortunately this pintle was unable to cope with the rotational movement of the bridge beams under modern day traffic loading and it eventually was replaced with a new pintle with a single block with a domed upper surface, this was undertaken in 1986 and the opportunity was taken to power operate the bridge. This resulted in a conflict between boaters and road traffic and in 1988 Road Barriers were added in the interest of public safety.
Bridge 49, Royal Oak, is heavily used by road traffic and has been fitted with a new deck - timber base with modern wearing surface - in January 2012.
Operation is electro-hydraulic and carried out by the boater using the CRT key in the adjacent control box. The controls require the presence of the operator throughout the process which can take up to ten minutes. The operator should ensure the boat is approaching the bridge before operation which will begin by lowering the road barriers and closing the highway to vehicular traffic. This is followed by the hydraulic removal of the support wedges from beneath the bridge. Only then will the bridge swing. It will automatically stop when it reaches the fully open position. Once the boat or boats have passed through, the close button is depressed and the above process is reversed. When the barriers are fully up, permitting traffic flow to resume, the key may be removed from the control panel."
The pictures in the extract above can be seen if you visit the interesting website.
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