To avoid differences in car body height and hazardous gaps between tram and platform when passengers are boarding and alighting, HANNING & KAHL has added a system for levelling tram cars to its product portfolio. Vehicles have now been equipped with the HANNING & KAHL Hydraulic Levelling Systems and are in successful passenger operation.
The levelling system ensures that car bodies are kept at a defined level in all operating states and circumstances. Several functions are integrated such as automatic adjustment of wheel tyre wear, compensation of the primary springs in the bogie, as well as levelling of changes in height (caused by passenger change). Position, travel and pressure sensors are used to control and monitor levelling so that wayside and vehicle-dictated clearance limits are kept, thus guaranteeing operational safety at all times.
In general, the overall system consists of the following five main components:
1. Hydraulic unit (HZY)
The HZY is usedd for the generation of hydraulic pressure in the system. The device can operate the mechanical brake at the same time.
2. Valve control unit (HVU)
The HVU contains the valves for control of the lift cylinder and also pressure sensors for internal monitoring.
3. Lift cylinder (HYHZ)
The Lift Cylinder raises and lowers the car body modules. Position sensors integrated in the lift cylinder control and monitor position.
4. Electronic Control Unit (LCU)
The LCU is for control of the valves and for continuous monitoring of differences in height between the individual car bodies. There is a hardware interface and two independent bus systems for extensive data exchange.
5. Position sensors (DS)
The Position Sensprs control and monitor the relative position between car body and bogie.