Railway. From the opening of the station, the railways of northern Switzerland developed rapidly, and by 1853 the Swiss Northern Railway had been merged into the Swiss Northeastern Railway (Schweizerische Nordostbahn; NOB). Also in 1853, the tracks in the station were regauged to the standard gauge () that is still used by all lines in the station. In 1856, the NOB completed its line from the station to Winterthur via the Wipkingen Tunnel and Oerlikon. In 1858, the NOB completed its line from Baden via Brugg to Aarau, where it connected with the Swiss Central Railway (Schweizerische Centralbahn; SCB), thus providing connections to Basel, Solothurn and Lausanne. With further railways planned, it became clear that the 1847 station was not large enough. A rebuild was started to meet Zürich's increased transport needs, albeit on the same site and using the same basic layout. The 1871 station In 1871, the replacement station building opened, to a design by architect . Its main entrance is a triumphal arch facing the end of the then newly built Bahnhofstrasse. In front of the arch stands a monument to the railway pioneer Alfred Escher. The magnificent sandstone neo-Renaissance building features richly decorated lobbies and atriums, restaurants and halls. Originally housed inside it was the headquarters of the Schweizerische Nordostbahn (NOB). The train shed, spanned by iron trusses, initially covered six tracks. Its stone walls with arches and arched windows portrayed a simple, monumental impression of space. The station was named Zürich Hauptbahnhof in 1893, to reflect that year's incorporation of many of Zürich's suburbs into an enlarged municipality. In 1902, the year in which the Swiss Federal Railways (SBB) took over the Schweizerische Centralbahn and the NOB, the tracks inside the eastern end of the train shed were lifted, due to a lack of space. Since then, these tracks have terminated at a more central location, immediately to the north of the Bahnhofstrasse. Also in 1902, four more tracks and a north wing with a restaurant and railway mail service were added to the north of the train shed. In the vacant space left inside the train shed, new rooms were built for baggage handling. On 18 February 1916, the SBB decided that electrification of its network would be by the high-tension single-phase alternating current system that is still used on all routes. On 5 February 1923, the electrified Zug–Zürich railway was put into operation,