Liverpool and Manchester Railway, built in 1830. Steam power continued to be the dominant power system in railways around the world for more than a century. Electric power introduced The first known electric locomotive was built in 1837 by chemist Robert Davidson of Aberdeen in Scotland, and it was powered by galvanic cells (batteries). Thus it was also the earliest battery electric locomotive. Davidson later built a larger locomotive named Galvani, exhibited at the Royal Scottish Society of Arts Exhibition in 1841. The seven-ton vehicle had two direct-drive reluctance motors, with fixed electromagnets acting on iron bars attached to a wooden cylinder on each axle, and simple commutators. It hauled a load of six tons at four miles per hour (6 kilometers per hour) for a distance of . It was tested on the Edinburgh and Glasgow Railway in September of the following year, but the limited power from batteries prevented its general use. It was destroyed by railway workers, who saw it as a threat to their job security. Werner von Siemens demonstrated an electric railway in 1879 in Berlin. The world's first electric tram line, Gross-Lichterfelde Tramway, opened in Lichterfelde near Berlin, Germany, in 1881. It was built by Siemens. The tram ran on 180 volts DC, which was supplied by running rails. In 1891 the track was equipped with an overhead wire and the line was extended to Berlin-Lichterfelde West station. The Volk's Electric Railway opened in 1883 in Brighton, England. The railway is still operational, thus making it the oldest operational electric railway in the world. Also in 1883, Mödling and Hinterbrühl Tram opened near Vienna in Austria. It was the first tram line in the world in regular service powered from an overhead line. Five years later, in the U.S. electric trolleys were pioneered in 1888 on the Richmond Union Passenger Railway, using equipment designed by Frank J. Sprague. The first use of electrification on a main line was on a four-mile section of the Baltimore Belt Line of the Baltimore and Ohio Railroad (B&O) in 1895 connecting the main portion of the B&O to the new line to New York through a series of tunnels around the edges of Baltimore's downtown. Electricity quickly became the power supply of choice for subways, abetted by the Sprague's invention of multiple-unit train control in 1897. By the early 1900s most street railways were electrified. The London Underground,