The S1 is a commuter rail route forming part of the Milan suburban railway service (), which converges on the city of Milan, Italy.
The service operates over the Milan–Saronno, Milan Passante, and Milan–Bologna lines. Like all other Milan suburban railway service routes, it is operated by Trenord.
Route
S1, a cross-city route, heads in a southeasterly direction from Saronno to Milano Lancetti. From there, it runs via the Milan Passante railway through the municipality of Milan to Milano Rogoredo, and finally to Lodi. The travel takes 1h29'.
History
The S1 was activated on 12 December 2004, and operated initially between Saronno and Milano Porta Vittoria.
With the change of timetable on 15 June 2008, the service was extended from Milano Porta Vittoria to Milano Rogoredo, where there is interchange with regional trains and long-distance services to and from Genoa, Bologna and Mantua.
To coincide with another timetable change on 13 December 2009, the service was further extended, from Rogoredo to Lodi, during the day in off-peak hours. From 13 June 2010, all other Monday to Friday services were extended to Lodi.
At June 2023, all trains run from Saronno to Lodi up to 9.30 p.m; after that and until the end of service, trains are limited to Lodi-Milano Bovisa, where it is possible to cover the remaining part of the route thanks to an interchange with line S3.
Stations
The stations on the S1 are as follows (stations with blue background are in the municipality of Milan):
Scheduling
, S1 trains ran half-hourly between 06:00 and 21:00 Monday to Friday.