Volume Eleven - Pre-Victorian to the Present Day - some more aspects - The Steam Navvy and the Dock Extension of 1883 . . .

So successfully performed has it fulfilled the purpose in view, that its use on all works of any magnitude, at least in this country, is the in rule rather than the exception ; and its manufacture forms an important branch of the business at the writer's works, from which upwards of a hundred of these machines have now been turned out, the majority for use in Great Britain, and the remainder distributed in various parts of the world.

Among the completed works on which it has been employed with special success may be mentioned the following : Victoria Dock, London ; Coble Dene Dock, Tynemouth ; Penarth, Swansea, Silloth, and Greenock Docks ; new outfall works at Boston ; harbour works at Calais, and at Melbourne, Australia ; cuttings on the Great Northern and the London and North Western Railways at Melton Mowbray, the Midland Railway at Manton and Bootle, the Dover and Deal Railway at Dover, the Rugby and Northampton, the Paisley, and the Didcot and Southampton Railways, the Lanarkshire lines at Airdrie, the North-Eastern Railway at Bishop Auckland, the Guildford and Surbiton, and the Rhymney Railways ; and other works.

The steam navvy excavates and delivers into wagons any material capable of being cut, such as sand, gravel, chalk, and clays of all kind, digging out with equal facility the hardest and toughest, such as require blasting when worked by hand. It can also deal with these materials when thickly interspersed with stones and heavy boulders ; and without being unduly strained it cuts through seams of flint, shale, slate, or even sandstone, which may intersect the face of the excavation it is at work upon. With the assistance of blasting, it is also used with advantage in much more difficult stuff, such as hard marl and lias rock.

Development. — Since its introduction many improvements have been made, increasing its power and efficiency. The framework has been considerably strengthened throughout, augmenting the total weight by several successive increments from 22 tons in the earliest machine to 32 tons, which is now adopted as the standard ; the scoop averages a capacity of about 25 per cent. larger than at first, and has an increased angular range. The duty has progressed in a greater ratio, nearly 50 per cent. having the been added to the original output. At first 180 to 190 wagon-loads were considered a good day's work ; now 240 to 250 are often obtained, and even more under very down favourable conditions : the day consisting of ten hours, and the wagons being the size ordinarily used by contractors, holding three cubic yards each ;