Progress of the Great Exhibition building: the traversing platform used in the construction of the nave, 1861. ...the most astonishing and the most extensive of [the] labour-saving contrivances is a gigantic travelling scaffold, which has been built on twelve wheels, to run on rails up and down the whole length of the centre nave. This huge structure is 60 ft. square and 100 ft. high, and weighs nearly 300 tons. Yet...four men with levers can move it with a certain amount of rapidity to any part of the works. It will be used in hoisting the upper columns, the huge circular wooden ribs of the roof, for painting, or, indeed, for any purpose connected with the building where many men have to be employed at a great height. The International Exhibition of 1862, or the Great London Exposition, was a worlds fair held from 1 May to 1 November 1862, beside the gardens of the Royal Horticultural Society, South Kensington, London, on a site that now houses museums including the Natural History Museum and the Science Museum. From "Illustrated London News", 1861.