The R9 is a railway service of RER Vaud that provides hourly service between and in the Swiss cantons of Vaud and Fribourg, respectively. Swiss Federal Railways, the national railway company of Switzerland, operates the service. The service was previously known as the S9.
The R9 operates every hour between and , using the LausanneâÂÂBern line between Lausanne and , and the PalézieuxâÂÂLyss line between Palézieux and . The R9 runs as an express between Lausanne and Palézieux, stopping only at . The S40 and S40 make local stops, combining with the R8, R9 and the InterRegio 15 for service roughly every 15 minutes. North of Palézieux, the R8 pairs with the R9 for half-hourly service to . Between Payerne and Murten/Morat, the Bern S-Bahn S5 runs hourly to and the S52 runs limited service to Payerne.
RER Vaud introduced the S9 designation with the December 2015 timetable change, replacing the S21. Both routes operated between Lausanne and Payerne. The S9 was extended from Payerne to Kerzers in December 2017.
On 10 December 2023, all RER Vaud lines were renamed as "R" and a number, instead of "S". In December 2024, the R9 was cut back from to Murten/Morat and extended from Lausanne to , replacing the R5 and R6 on that section.