When I first saw Tower Bridge up close and personal in 2008 my first thought was “Wedding Cake!” Because the bridge is literally an explosion of beauty and functionality at the same time.
Our hotel was next to the bridge, although the sun did rule out any photography from the late afternoon, and I was never much good with “night shots”.
I visited “The Engine Room” at the time and it was one of those glorious cathedrals of huge silent machines and polished brass. The bridge is a combined bascule and suspension bridge and was built in 1886–1894. It is now owned and maintained by the Bridge House Estates, a charitable trust overseen by the City of London Corporation.
There are 4 boilers of which two were fired up at any one time to supply steam to the pumping engines. Two steam engines provided enough power to operate the bridge. The ram sucked water from the storage tank and and pumped it into the hydraulic pump system. There were 6 hydraulic accumulators: two in the pumphouse and two in each pier, maintaining a constant pressure in the pipe system. Two out of the 8 bascule drive engines were capable of raising the bascules. Horizontal cylinders and single acting pistons rotated the crankshaft which moved the rack pinions (or cogs). Expanded water went back into the storage tank by way of the return pipe. The 2 bascules weigh 1200 tonnes each and are supported in pivots and balanced by counterweights. Above the counterweight is a quadrant with gear teeth on the outer edge. The rack pinion engages the teeth and its rotation causes the bascule to move up or down through a maxim arc of 83 degrees. (information board at the engine room)
At the time It was too late in the afternoon to visit the bridge itself so it was added to my long list of things to see/do in London if/when I ever got there again.
In 2013 I got there again, and this time I went on the bridge tour. I cannot give an exact date when this happened but I think it was on the same day that I did the mammoth walk. I covered a lot of ground on these excursions though, but this one was very early in March 2013.
The tour takes you up the southern tower by lift, across the walkway and down the other tower. The surprising thing is that instead of the towers being solid structures they are really hollow spaces with girders and stairs and nothing more substantial than that. Granted, the building was a product of the Victorian age so even the inside was spectacular.
The biggest design consideration was that sailing ships must be able to pass underneath it, ruling a normal flat bridge out. The design that was approved was submitted by Sir Horace Jones, the City Architect. He was also one of the judges of potential designs. His engineer, Sir John Wolfe Barry, devised the idea of a bascule bridge with two towers built on piers. The central span would consist of two bascules of the same length which could be raised to allow ships to pass underneath. The two side-spans were suspension bridges, with the suspension rods anchored both at the abutments and through rods contained within the bridge’s upper walkways. (https://en.wikipedia.org/wiki/Tower_Bridge)
As far as I know the walkway between the towers was a popular place for the Victorians to promenade, in fact it is a pity that they don’t open them up once again for regular use, although the “‘ealth ‘n safety” implications would be onerous.
The view from the walkways is stunning. (the images below are 1500 pixels long and open in a new tab)
And then it was time to go. The walkways were altered slightly not too long ago and I believe that there is a clear glass panel that allows you to view the street below. No thanks, I may give that a miss.
I have seen the bascules raised a number of times, and in June 2016 saw it from a different angle.
I also was close and personal when a ship went through the raised bascules.
This is the raised roadway, and the bascules were raised at least 10 minutes before the ship went through and the traffic stacked up very quickly behind the barricades. At least when it was built the traffic jams would have been much smaller than they are now, although the bascules would have been raised more often because of the amount of shipping passing beneath to access the Pool of London.
Whichever way you look at it, Tower Bridge epitomises London and is probably one of the most easily recognised bridges in the world. It comes from an era when aesthetics were as equally important as good engineering. It has been with us over a century, and if properly maintained could be around for another. I am fortunate to have seen it up close and personal, and I still think it looks like a wedding cake, and a glorious wedding cake it is indeed.
© DRW 2013-2018. Created retrospectively 05/03/2017