S21

S21 or S-21 may be:

S₂₁ may refer to :

St. Gallen–Trogen railway line

The St. Gallen–Trogen railway line, or Trogenerbahn (TB), is a 9.8 kilometres (6.1 mi) long railway line in Switzerland. It links the city of St. Gallen,in the canton of St. Gallen, with Speicher and Trogen, both in the canton of Appenzell Ausserrhoden. Passenger service on the line now forms part of the St. Gallen S-Bahn, branded as the S21.

The line was opened in 1903, and was built as a rural electric tramway. Whilst much of the line has been upgraded, this is still apparent in the long stretches of roadside track, and in its exit from St. Gallen over street track. With a gradient of 7.6%, it is the steepest narrow-gauge adhesion railway in Switzerland.

The line is owned and operated by the Appenzell Railways company, which also operates several other railway lines in the two Appenzell cantons.

History

The line was opened on the 10 July 1903 by the Trogenerbahn AG company, with its headquarters in Trogen. From its terminus at St. Gallen railway station to the Brühltor, the line used the tracks of the St. Gallen city tramway.

S21 (Berlin)

S21 is a term of the Berlin S-Bahn with several usages:

History

The two former services were always operated with 15 kV, 16.7 Hz AC overhead lines while all other S-Bahn lines in Berlin were and are operated with 800 V DC third rail. It was operated by Deutsche Bahn.

First operation in 2006

S21 service was introduced with the opening of the Berlin North-South mainline and the new Berlin Hauptbahnhof central station. DBAG Class 423 trains were used, these trains were lend from the Munich, Stuttgart and Frankfurt S-Bahns. The first S21 service was discontinued on July 11, 2006.

Second operation in 2009

In 2009 the S-Bahn service had to be strongly shortened due to lack of rolling stock. As a replacement and addition for the Nord-Süd-Tunnel-S-Bahn (S1, S2, S25 lines) the S21 ran again. Some S21 trains were extended to Hennigsdorf as a replacement for S25. This time trains of the Munich, Stuttgart and Rhine-Ruhr S-Bahns were used.