The KISS double-deck electric trains, ordered by Azerbaijan Railways CJSC (ADY) from the Swiss company Stadler Rail Group, were first brought to Azerbaijan in 2015. These trains began operating on the Baku-Sumgayit route on September 12, 2015, with President Ilham Aliyev attending the launch ceremony. Currently, 9 KISS electric trains are in service on Azerbaijan's railways, running on the Absheron Circular railway line and the Baku-Gabala-Baku route.
The passenger capacity of double-decker electric trains varies between 370-400 (370 seats in 4 trains; 396 seats in 5 trains). They consist of three standard and one business-class carriages. Four trains designed for interregional routes feature a first-class lounge in the business carriage. Each carriage is equipped with air conditioning and bio-toilets.
Based on a contract signed in November 2019 between ADY and Stadler Rail Group, Azerbaijan acquired 6 electric and 4 diesel FLIRT trains. Each single-deck train consists of 5 cars and has a passenger capacity ranging from 236 to 270 people.
The trains offer standard, standard plus, business, and first-class (8 seats) seating. They feature spacious bar-car lounges and are equipped with air conditioning and bio-toilets.
The diesel trains operate without a contact network, using internally generated electricity produced by their own engines.
The express passenger train, refurbished and modernized in Slovakia, operates on the Baku-Sumgayit-Baku and Baku-Aghstafa-Baku routes. It consists of one business class and several standard cars.