prone to delays. There are three preserved trains, number 170 082 known as a 'museum train' and numbers 470 128 with 471 082 known as 'traditional trains'. These trains are used for different events throughout the year and in particular in the lead up to Christmas. Stations The S-Bahn has 68 stations, of which ten are fully underground. These are the five stations along the City-S-Bahn (Jungfernstieg, Stadthausbrücke, Landungsbrücken, Reeperbahn and Königstraße), the S-Bahn area of Altona station, the three stations in the centre of Harburg (Harburg, Harburg Rathaus and Heimfeld) and at Hamburg Airport. At the Hauptbahnhof, the westbound platforms are also in tunnel. Most stations consist of a single island platform. At the interchange stations Hauptbahnhof and Altona there are two island platforms, one for trains to the city centre and one for the other direction. At Neugraben and Pinneberg termini the two S-Bahn tracks are between a side platform and an island platform, on the other side of which regional rail trains stop. Side platforms are at the triple-track stations at Bergedorf, Berliner Tor (lower level), Blankenese and Harburg Rathaus, the twin-track station at Billwerder-Moorfleet and at the only single-track station, Iserbrook. All stations have electronic passenger information systems showing information about the line, destination, route, length and stopping position of the next train, missed connections and temporary disturbances to service. Some stations, for example Landungsbrücken and Harburg Rathaus, are designed as civilian shelters. The heavy protective entrance doors are the only sign of this dual use. Service time and intervals Trains run daily from about 04:30 to 01:00. There is an all-night service within the Hamburg section on the nights before Saturdays, Sundays, and public holidays in Germany. The base frequency for lines S1, S21, S3 and S31 during the day is 10 minutes; before 06:00, after 23:00 and during weekend night service, the frequency is 20 minutes. Multiple lines running on the same tracks, mainly through the city centre but also along the routes served by the S2/S21 and the S3/S31, have shorter intervals. Peak-time lines S2 and S11 decrease intervals in the morning and afternoon. See also List of Hamburg S-Bahn stations Hamburg U-Bahn AKN Eisenbahn List of metro systems References Literature Erich Staisch: Die Hamburger S-Bahn. Chronik eines modernen Verkehrsmittels., Hamburg 1984, (German) Erich Staisch (Hrsg.): Die Hamburger S-Bahn. Geschichte und Zukunft., Hamburg 1996, (German) Wolfgang Pischek, Jan Borchers, Martin Heimann: Die Hamburger