Most prominent among those who took an active interest in the development of the locomotive were George Stephenson and his son, Robert. Stephenson’s first locomotive was tried on the Killingworth Railway on July 27, 1814. In 1815 Dodds and Stephenson patented an arrangement for attaching the connecting rods to the driving wheels, which took the place of cog wheels heretofore employed, and in the following year Stephenson, in connection with Mr. Losh, patented the application of steam cushion-springs for supporting the weight of the locomotive in an elastic manner. In 1825 the Stockton and Darlington Railway, in England, was opened for traffic, with George Stephenson’s engine, “Locomotion,” and was put permanently into service for the transportation of freight and passengers. [Illustration: FIG. 96.--HACKWORTH’S LOCOMOTIVE, “ROYAL GEORGE,” 1827.] In 1827 Hackworth produced the “Royal George” (see Fig. 96), whose cylinders were arranged vertically at the rear end of the boiler, and whose pistons emerged from the cylinders at the lower ends of the latter, and imparted their power through connecting rods to cranks on the opposite ends of the axle of the rear driving wheels in a more direct manner than heretofore, and doing away with the overhead mechanism heretofore employed in most engines. Hackworth also improved the steam blast, put on the bell, and greatly simplified and modernized the appearance of the locomotive. [Illustration: FIG. 97.--GEORGE STEPHENSON’S “ROCKET,” 1829.] In 1829 the Liverpool and Manchester Railway was completed, and the directors offered a prize of £500 for the best locomotive. George Stephenson’s “Rocket,” shown in Fig. 97, attained a speed of 24⅙ miles an hour, and took the prize. Its success, however, was marred by the first railroad fatality, for it ran over and killed a man on this occasion. It embodied, as leading features, the steam blast and the multitubular boiler, which latter was six feet long and had twenty-five three-inch tubes. The fire box was surrounded by an exterior casing that formed a water jacket, which, by means of pipes, was in open communication with the water space of the boiler. [Illustration: FIG. 98.--“STOURBRIDGE LION,” 1829.] The first practical locomotive to run on a railroad in the United States was the “Stourbridge Lion,” seen in Fig. 98. This was imported from England, and arrived in New York in May, 1829, and was tried in that year on a section of the Delaware & Hudson Canal Company’s railroad. The boiler was tubular, and the exhaust steam was carried into the chimney by a pipe in front of the smoke stack as shown. It had vertical cylinders of thirty-six inch stroke, with overhead grasshopper beams and connecting rods. [Illustration: FIG. 99.--LOCOMOTIVE “JOHN BULL,” 1831.]