Member of Parliament and Solicitor to the City of London Charles Pearson campaigned for an underground rail service in London. Parts of the first such railway, the Metropolitan Line, opened to the public in 1863, thereby becoming the first subway line in the world. Trains were originally steam-powered, but in 1890, the first electric trains entered service. That same year, the whole system became officially known as the Tube after the shape of the rail tunnels. (It was not until 1908 that the name London Underground was introduced.)