In future, the availability of information on actual service loads will become increasingly important in the design of rail-bound vehicles for urban traffic - particularly in connection with the development of new vehicle concepts, but also with a view to verifying or modifying current load assumptions based on existing standards and regulations. Another aspect to be considered is that rail-bound vehicles in urban transport normally do not leave their own network. The construction and maintenance of rail networks for urban traffic nowadays takes place essentially on the basis of operator-specific specifications. Wheel force transducers are widely used in the car and commercial vehicle industry to determine forces and moments of vehicles in operation, relevant for multiple tasks within the development process of the manufacturers. In the rail industry technologies wheel measuring systems for resilient wheels are until today not available. On trams even such installations are often not applicable to geometrical restrictions and the design. With the development of the new rail measuring wheel LBFR-Wheelos (Rail Wheel Load Sensor) a multi-axial sensor is presented, which is based on many years of experience in road vehicle wheel force transducers. It allows the determination of the vertical, lateral and longitudinal forces as well as the respective torques. It additionally provides the information about the actual contact point of the wheel tire on the rail, since all six load components are measured highly accurate. The decisive improvement of the reliability of measured load conditions allows allow to improve essentially the dimensioning of wheels, axles and bogies as well as the body of rail vehicles. Test programs and load assumptions for the numerical simulation can be derived. This paper presents the technology of the LBFR-Wheelos on the example of a tram wheel. Like in the road vehicle industries it is expected that this wheel force transducer technology will be introduced to other rail vehicles in the regional and high-speed rail traffic.