implemented as part of the mainline railway line. Incidentally, Ghega had already worked out a belt railway project along the line wall in 1845. The first planning for a subway in deep-seated tunnels by Emil Winkler dates back to 1873, in which it is also remarkable that the planning proposals were also based on the first systematic traffic census in Vienna. Another wave of public transport projects were developed as the ring road was close to be finished. The conception of the British engineers James Bunton and Joseph Fogerty convinced, since their plans were approved in 1881, which included trains to be run in tunnels, in open incisions, and on elevated tracks. In 1883, the project of an "electric secondary railway" of the company Siemens & Halske provided a small profile rail with three lines. The construction failed due to the concern of the city council, the inner city business life could be affected, especially since the project for the first time ever included a tunneling of the city center. The first system to be constructed was a four-line Stadtbahn railway network (which had been planned to have three main and three local lines) using steam trains. Ground was broken in 1892, and the system was opened in stages between 11 May 1898 and 6 August 1901. At Hütteldorf, the Stadtbahn connected to railway service to the west, and at Heiligenstadt, to railway service on the Franz Josef Line, which then ran eastwards within the Austro-Hungarian Empire to Eger. Some of the Jugendstil stations for this system designed by Otto Wagner are still in use. However, the Stadtbahn proved inadequate for mass transport, less successful than the tramway. Starting in 1910, plans were considered for an underground system, but were interrupted by the First World War, which also necessitated closing the Stadtbahn to civilian use. After the war, the economic situation of a smaller and poorer country ruled out continuing with the plan. However, starting on 26 May 1924 the Stadtbahn was electrified, something that many had called for before the war, and from autumn 1925 it was integrated with the tramway rather than the railways. The frequency of trains tripled. Plans for a U-Bahn dating to 1912–14 were revived and discussions took place in 1929, but the Great Depression again necessitated abandoning planning. Both in 1937 and after the Anschluß, when Vienna became the largest city by surface area