Rail vehicle group (2a, 2b, 2c), comprising m rail vehicles (4a - 4d), each of which has an underfloor region, n device units (26, 26a - 26e) arranged one after another in the vehicle longitudinal direction in its underfloor region, and a first and a second set of running gear (22, 24), where m and n are natural numbers greater than 1 and, in each of the m rail vehicles (4a - 4d), each of its n device units (26, 26a - 26e) is of the same type as one of the n device units (26, 26a - 26e) of each other of the m rail vehicles (4a - 4d), and at least one of the m rail vehicles (4a - 4d) is a motor unit and at least one of the m rail vehicles (4a - 4d) is a carriage, characterized in that for all i from 1 to n - in each of the m rail vehicles (4a - 4d), the i th of its n device units (26, 26a - 26e) in the vehicle longitudinal direction is of the same type as the i th of the n device units (26, 26a - 26e) in the vehicle longitudinal direction of each other of the m rail vehicles (4a - 4d), - in each of the m rail vehicles (4a - 4d), the i th of its n device units (26, 26a - 26e) in the vehicle longitudinal direction is at a predefined distance from its first set of running gear, wherein the distance of the i th device unit (26, 26a - 26e) in the vehicle longitudinal direction of the respective rail vehicle (4a - 4d) to its first set of running gear is the same in all m rail vehicles (4a - 4d), and - the underfloor region of the respective rail vehicle (4a - 4d) has a subregion for individual equipment with vehicle components, wherein, in the motor unit, vehicle components that are different from those in the carriage are arranged in its subregion that can be equipped individually, where i is a natural number and in each of the m rail vehicles (4a - 4d) the vehicle longitudinal direction is oriented from its first set of running gear towards its second set of running gear. for all i from 1 to n - in each of the m rail vehicles (4a - 4d), the i th of its n device units (26, 26a - 26e) in the vehicle longitudinal direction is of the same type as the i th of the n device units (26, 26a - 26e) in the vehicle longitudinal direction of each other of the m rail vehicles (4a - 4d), - in each of the m rail vehicles (4a - 4d), the i th of its n device units (26, 26a - 26e) in the vehicle longitudinal direction is at a predefined distance from its first set of running gear, wherein the distance of the i th device unit (26, 26a - 26e) in the vehicle longitudinal direction of the respective rail vehicle (4a - 4d) to its first set of running gear is the same in all m rail vehicles (4a - 4d), and - the underfloor region of the respective rail vehicle (4a - 4d) has a subregion for individual equipment with vehicle components, wherein, in the motor unit, vehicle components that are different from those in the carriage are arranged in its subregion that can be equipped individually, - in each of the m rail vehicles (4a - 4d), the i th of its n device units (26, 26a - 26e) in the vehicle longitudinal direction is of the same type as the i th of the n device units (26, 26a - 26e) in the vehicle longitudinal direction of each other of the m rail vehicles (4a - 4d), - in each of the m rail vehicles (4a - 4d), the i th of its n device units (26, 26a - 26e) in the vehicle longitudinal direction is at a predefined distance from its first set of running gear, wherein the distance of the i th device unit (26, 26a - 26e) in the vehicle longitudinal direction of the respective rail vehicle (4a - 4d) to its first set of running gear is the same in all m rail vehicles (4a - 4d), and - the underfloor region of the respective rail vehicle (4a - 4d) has a subregion for individual equipment with vehicle components, wherein, in the motor unit, vehicle components that are different from those in the carriage are arranged in its subregion that can be equipped individually, where i is a natural number and in each of the m rail vehicles (4a - 4d) the vehicle longitudinal direction is oriented from its first set of running gear towards its second set of running gear.