U-Bahn are scheduled to be completed in the upcoming decade, finally creating the missing line U5. Upon completion of the U5 and U2 projects, there will then be a network that is long with 116 stations. Some plans have been proposed for the system beyond 2027, when the U2/5 project gets completed, although such plans are currently unfunded. U-Bahn services run between 05:00 and around 01:00 at intervals between two and five minutes during the day and up to eight after 20:00. Since 4 September 2010, there has been a 24-hour service operating at a 15-minute interval in the nights between Fridays–Saturdays, Saturdays–Sundays, and in the nights prior to a public holiday. The 24-hour U-Bahn is supplemented in these nights by Vienna NightLine bus services. Stations Map History and projected expansions Planning for an underground railway can be traced back to the 1840s. Since then, there have been numerous plans and concessions to build such a project, making Vienna the city with the most subway planning. The concession request of the engineer Heinrich Sichrowsky dates from 1844 with the idea of an atmospheric railway based on the system of Medhurst and Clegg. The trains would have been advanced by means of air pumps stationarily stationary steam engines in a pneumatic manner. Sichrowskys route should lead from the Lobkowitzplatz below the Vienna Glacis on to the Wien River to Hütteldorf. Although such trains had been built in London and Paris, it found in Vienna no investors for its stock company, so this idea was rejected. The connecting railway project of Julius Pollak (1849) was also conceived as an atmospheric system. Sichrowsky's request was the starting point for a series of plans that, however, were mostly not approved and could not be implemented. For example, in 1858 the city planner Ludwig Zettl proposed to make an overburden of the former moat instead of filling it, and then to set up a railroad tram in this enclosed ditch, which would bypass the city. This would have created a connection between the central station and the market halls, while at the same time the gas-lit tunnels were to serve as warehouses for food. By 1873, at least 25 planning for a municipal railway traffic came on, only the Verbindungsbahn, which already appeared in the much larger overall plan by Carl Ritter von Ghega in his project for Vienna's urban expansion of 1858, was later