Léman Express is a joint venture or joint maketing name of the Swiss Federal railroads SBB CFF FFS and of the French state railways SNCF. Léman Express operates local trains in the surroundings of the city of Genève (Geneva) and most of the lines cross the Swiss-French border. Two kinds of trains are used for the Léman Express services: Swiss SBB's Stadler FLIRT trains of the Swiss class 522 and French SNCF's new Alstom Regiolis trains. Bothe types can operate as well with the Swiss 15 kV AC electric system as the French DC system and they are equipped with security systems of both countries.

This train is one of the Swiss Stadler FLIRT trains of the Swiss class 522, which is a four coaches long FLIRT version capable of operating in both Switzerland and France.
Picture from Genève Eaux-Vives station 8.2.2020 by Ilkka Siissalo.

Front part of the same Léman Express FLIRT as above. All Léman Express trains carry these extra blue stripes as their identification.
Picture from Genève Eaux-Vives station 8.2.2020 by Ilkka Siissalo.

Another RABe 522 FLIRT of the Léman Express service.
Picture from Genève Cornavin station 8.2.2020 by Ilkka Siissalo.

The network of Léman Express trains.
Picture from Genève Eaux-Vives station 8.2.2020 by Ilkka Siissalo.

These are the new French trains which operate on the Léman Express services. The train is an Z31500 Régiolis, built by Alstom. This type is a three-current version, capable of running under 25 kV AC 50Hz, 15kV AC 16,7 Hz and 1500V DC.
Picture from Evian-les-Bains 8.2.2020 by Ilkka Siissalo.

A bit closer look at the same train as above.
Picture from Evian-les-Bains 8.2.2020 by Ilkka Siissalo.

Another similar Régiolis train in Evian.
Picture from Evian-les-Bains 8.2.2020 by Ilkka Siissalo.

The RER train between Genève Cornavin and La Plaine was a very special trainline and a precursor of the present day Léman Express trains. It was a 1435 mm normal gauge short line from Genève's main station Cornavin to the suburban village of La Plaine, but it was electrified with the French 1500 V DC system instead of the Swiss normal 15 kV AC. This was because at Cornavin it shared some tracks with local trains coming from France. The trains used were further developments of the Lausanne city metro, built by Ateliers Vevey. Today the line has been converted into a 25 kV AC line system and the service has been extended from La Plaine to Bellegarde. The line is now served with trains of line L5 and L6 of the Léman Express service.

Here is still one of the special RER Genève - La Plaine trains. Picture is from Genève Cornavin 26.1.2003 by Ilkka Siissalo.

Another view of a RER train between Genève Cornavin and La Plaine.

Picture from Genève Cornavin 26.1.2003 by Ilkka Siissalo.

The RER trains between Genève Cornavin and La Plaine were operated jointly by the Swiss federal railways and TPG, which is the public traffic section of City of Genève and the operator of Genève's trams.

Picture from Genève Cornavin 26.1.2003 by Ilkka Siissalo.