Mellingen is a historic town and a municipality in the district of Baden in the canton of Aargau in Switzerland. The town is located on the Reuss.

The Zürich S-Bahn system is a network of rail lines that has been incrementally expanded to cover the ZVV area, which comprises the entire canton of Zürich and portions of neighbouring cantons, with a few lines extending into or crossing the territory of southern Germany. The network is one of many commuter rail operations in German speaking countries to be described as an S-Bahn. The lines connect with services of Aargau S-Bahn to the West, Basel S-Bahn and Schaffhausen S-Bahn to the North, St. Gallen S-Bahn to the East, and Lucerne S-Bahn/Zug Stadtbahn to the South, as well as with InterCity, InterRegio and RegioExpress services at major junction stations.