Motivation for a Vehicle in Underfloor Construction
The active suspensions of railway vehicles known to date and also those of the existing RailCabs have a relatively complex coach body and require comparably large installation space because of the cylinders being mounted vertically. This is why we developed an active chassis on which the body can be moved and turned in all directions and which, flat and compact, is mounted under the chassis floor. The space can be kept flat due to a horizontal mounting of the cylinders that transmit their motions to springs made of glass-fiber reinforced plastic (GRP) via a baffle plate. Modular construction allows cost-efficient production. With this new system an active suspension and a tilting system can be realised.
Principle of the Underfloor Suspension-/Tilt Technology
The largest space in vertical direction is occupied by the active suspension. Due to the modular construction of the RailCabs it is possible to adopt the existing drive along with the track guidance and redesign just the suspension. Clever arrangement of the technical parts allows mounting them “underfloor”. In this way additional useable space is gained and the body can be replaced far more easily.
For testing the new suspension/tilt technology as an underfloor construction we built up a testbed. The active modules are already identical with those that are going to be used in the vehicle later on. In order to simulate shocks induced by the rail and transmitted into the vehicle by the wheels, the testbed disposes of a hydraulic excitation unit. Extensive trials proved the new system to be efficient. In the process we were also very satisfied with the new GRP spring.