Murray's Locomotive Upon Blenkinsop's Railway, 1812.
Drawing constructed from a museum model (see Wescott below)
In 1851, a Mr. Blenkinsop of Leeds took out a patent for a machine and rail adapted to each other; a rack or toothed rail was to be laid down along one side of the track, into which a toothed wheel of his locomotive worked. The boiler of his engine was supported by a carriage upon four wheels without teeth and resting immediately on the axles. These curved entirely independent of the working parts of the engine and merely supported its weight, the progress being effected by the motion of the cogged wheels working on the cogged rail. This engine began running on the railroad from the Middleton collieries to the town of Leeds, about 3_ miles, on the 12th August, 1812. For a number of years, it was a permanent object of curiosity and was visited by crowds of strangers from all parts. These engines (for several were afterward constructed) drew after them 30 coal cars, loaded, at a speed of 3 miles per hour, and were in use for many years and may justly be considered as the first instance of the employment of locomotive power for commercial purposes.
WescottÕs description of BlenkinsopÕs Rack Locomotive (1812) is as follows:
Museum drawing based mainly an contemporary prints and descriptions. Two vertical cylinders, 9 in. by 22 in., driving separate cranks at right angles were geared to the rack wheel which worked in a rack cast on the edge rails on one side only of the track. The carrying wheels were not driven. Plug valves driven by fixed eccentrics. Reversing by turning plugs through 90 degrees. Cast-iron boiler. Weight about 5 tons. Inside wooden frame carried a small water tank. Flanged wheels.
The following description of MurrayÕs engine is from EllisÕs The Lore of the Train:
Now in those early eighteen-hundreds, one of the most formidable minds in the improvement of steam engines was Matthew Murray, whose name makes his Scots descent patently obvious. Only a Northern Englishman could have had a name like John Blenkinsop. Murray had invented the short D-shaped slide valve in 1806, greatly improving admission and exhaust events. Blenkinsop's contribution was propulsion by rack and pinion. The rack consisted of a closely regular set of teeth or lugs on the outside of the left-hand rail, and with these engaged a large cog which was the engine's driving wheel.
Our representation of the Murray-Blenkinsop locomotive (see above)) is made from a beautiful model in London's Science Museum, South Kensington. It is fairly self-explanatory, but the following points should be noted. The boiler, with a central furnace leading to a flue at the opposite end, had the two cylinders mounted vertically in the top of its shell. Power was transmitted through transverse crosshead beams to spur wheels both driving the main pinion axle. The exhaust led not to the chimney, as in Trevithick's first locomotive, but to an outlet between the cylinders. Possibilities of making the exhaust produce draught in the firebox had not occurred to Murray. But the open exhaust must have created abominable din, especially for people who had not been previously accustomed to engines moving about the country. Hence the large wooden silencer which occurs on the model and in the present drawing. Just when this was fitted cannot be accurately recorded; it is lacking in many of the old drawings.
Construction of the first Murray-Blenkinsop locomotive probably began during 1811, and it was certainly in regular traffic at Middleton in 1812, the year in which, be it added, James Fenton produced the spring-loaded safety-valve, a very desirable and important accessory which, however, did not prevent boilers from bursting now and then, usually because of the unsystematic inspection tolerated in early days.
Steam traction is recorded as having been inaugurated on August 12, 1812 with two locomotives named Salamanca and Prince Regent. This as suggested, was the world's first commercial use of steam haulage by locomotives on rails. Two more locomotives were added in the following year; Lord Wellington on August 4 and Marquis Wellington on November 23. The names of the engines reflect European power politics of the time, apart from the tribute to His Rather Rascally Royal Highness who later became George IV of the United Kingdom. The general, it will be noted, was not yet a duke, but was rising rapidly in aristocratic status. He had won at Salamanca, but not yet at Waterloo!
Rack-and-pinion propulsion was to continue on the Middleton Railway until 1835, by which time steam lines of orthodox sort were entirely established and appearing all over Europe and in many parts of North America. The principle then became dormant until it was revived, in less primitive form for steep-grade mountain railways, as on Mount Washington in the United States and very soon after on the Rigi in Switzerland.