[b3orn]

> S-Bahnen sind Eisenbahnen und fahren mit Bahnstrom, also 15 kV 16,7 Hz Wechselstrom.

Wrong, in Hamburg it uses 15 kV AC only on one track outside the city, everywhere else it's using 1200 V DC.

[majewsky]

Interesting. And Wikipedia explains that they intend to standardize on DC again. It appears the power aspect is a case of "Ausnahmen bestätigen die Regel".