Line S11, a radial route, heads initially in an southeasterly direction from Chiasso in Switzerland over the border to Como San Giovanni, and then south, to Camnago-Lentate.

[2] From 26 April 2015, has been extended to the station of Rho due to the start of Expo 2015 on 1 May 2015; currently, trains run hourly respectively between Rho and Como San Giovanni or between Milano Porta Garibaldi and Chiasso, for a combined half-hourly service between Como San Giovanni and Milano Porta Garibaldi on the S11.

The route was activated on 14 December 2008, and was initially an hourly regional rail service between its two termini, although it was designated at Chiasso station as the S11.

On 13 December 2009, the Italian part of the route was reclassified as the S11 suburban rail line.

The stations on the S11 are as follows (the stations with a coloured background are within the municipality of Milan):[3] As of 2023, S11 trains run half-hourly between Milano Porta Garibaldi and Como San Giovanni Monday to Sunday, with one train per hour serving alternatively up to Rho (from Milano Porta Garibaldi) or up to Chiasso (from Como San Giovanni).