The invention relates to a rail vehicle system having a set of carriages (12.1-12.7), which are provided for transporting passengers, wherein the set has two end carriages (12.1, 12.7), at least one driveless central carriage (12.3, 12.6) and at least one central carriage (12.2, 12.4, 12.5) that is designed as a traction carriage having at least one drive unit (16.2, 16.4, 16.5). In order to achieve greater flexibility in assembling a rail vehicle system, in particular with regard to improved scalability of the traction power, according to the invention the traction carriage comprises a power supply unit (22.2, 22.4, 22.5), which is provided for the drive unit (16.2, 16.4, 16.5) and has at least one voltage transformer unit (24.2, 24.4, 24.5) and one power converter unit (28.2, 28.4, 28.5).