Patent ID: 7168370

Claim:
A secondary suspension system for a rail vehicle comprising: a superstructure; a bogie arranged below the superstructure; a level control to control levels of the superstructure; a hydropneumatic spring unit, located between the superstructure and the bogie, the hydropneumatic spring unit ensuring at least one raised travelling level for the superstructure during travel of the rail vehicle and being adjustable to provide a lowered station platform level; a suspension accumulator assigned to the hydropneumatic spring unit, the suspension accumulator being blockable by the level control when the vehicle is stopped to prevent a change of level of the rail vehicle during a change of loading of the rail vehicle; and further including at least one emergency spring cylinder which, in an emergency operation caused by at least one of the following a) a pressure drop and b) a pressure failure, a moving out of the emergency spring cylinder ensures an emergency spring level between the lowered station platform level and the at least one travelling level.