In 1877 a rack railway was built to connect the lakeside resort of Ouchy to the city centre.
Service is provided by only one single-carriage running up and down without a break.
Actually the busiest of all three metro lines. It's almost entirely single track except at most stations where trains cross each other. Operating from 6 - 20h at a 10 minute interval. The line is especially busy with students travelling to the EPFL and UNIL University campus. All metro lines meet at Flon on the same level, station platforms form a right angle.