Twenty 3-car and 4-car Stadler FLIRT EMUs were ordered and are used on all four lines. The 3-car vehicles can carry 343 (167 seated), the four-car vehicles 457 (219 seated). Three-car units are designated 427 (centre section: 827) and four-car units 428/828).
The vehicles were tested in November 2006 to test travels on the Friedberg-Hanau line of the HLB as well as the KBS 209.60 (operated by ODEG railway in which the HHA is involved). The HHA is also active in Hessen in the city bus services of Wiesbaden (WiBus) and Fulda (Fulda bus). In addition Cantus took part in the Bavarian subnetwork around Würzburg, which reaches Schlüchtern in a branch south of Fulda, but was subject to a competition procedure from DB Regio AG.