R1 (RER Vaud)

The R1 is a railway service of RER Vaud that provides hourly service between Grandson and Lausanne in the Swiss canton of Vaud. On weekdays, the line also runs between Lausanne and Cully. Swiss Federal Railways, the national railway company of Switzerland, operates the service. The service was previously known as the S1.

Operations
The R1 operates every hour between Grandson and Lausanne, using the southern portion of the Jura Foot Line. It is paired with the R2 (which does not make all local stops), providing half-hourly service between the two cities. On weekdays both the S1 and S2 operate between Lausanne and Cully. The R3 and R4 also operate between Cossonay-Penthalaz and Cully, raising the service frequency to every 15 minutes.

History
The S1 was one of the six original lines of the RER Vaud, then called the Vaud Express Network (Réseau express vaudois, REV), when that system was established in December 2004. It ran hourly between Yverdon-les-Bains and Villeneuve. With the December 2015 timetable change, the northern and southern termini of the S1 changed to Grandson and Lausanne, respectively. The RER Vaud lines were substantially reorganized for the December 2022 timetable change. The S1 was extended from Lausanne to Cully on weekdays. On 10 December 2023, all RER Vaud lines were renamed as "R" and a number, instead of "S."