Zürich Seebach railway station
Trains on the S6 provide a half-hourly connection to Zürich Hauptbahnhof station, taking 12 minutes for the journey via the southern connector and Oerlikon station. In the opposite direction, S6 trains continue to Baden station, taking 28 minutes for the journey. The station also sees significant through freight traffic, most of which takes the Furttal line in order to avoid passing through central Zürich, using the northern connector onto or off the Zürich–Winterthur line.
Australian railway signalling
Projected traffic density warranted the introduction of additional signal indications. One of these was a small green light under the two main red lights of a Stop signal, indicating Low Speed. The Low Speed indication was provided in the Underground City Railway from its opening on 28 February 1932. The standard speed restriction imposed by train stops with the Low Speed indication was originally 17 mph. However, at some locations, the maximum permissible speed is as low as 5 mph, subject to local conditions. In the Underground City and Eastern Suburbs railway lines, a speed restriction of 30 mph also applies to the Caution indication. The train stops can be seen dropping as the signals step-up to Medium. Closely spaced 'multi home signals', similar to those used on the London Underground, are also a feature of the Underground City and Eastern Suburbs lines. Speed control by intermediate train stops, based on Mr Byles' system, was introduced on the London Underground following the accident at Moorgate on 28 February 1975, in which 43 people were killed. These are spread out along the platform at major stations, mostly on the City Circle. When the signal at the end of platform is at stop, they will only drop when the train reaches a predetermined speed, which is lower as the train gets closer to the end of the platform. The last trip will only drop when the train is at around 5 km/h.