New Precise Level Control System from Liebherr for Chicago’s Light Rail System
The intelligent hydraulic level control system made by Liebherr adjusts the level of the vehicle floor to the level of the station’s platform.
Getting on and off trains over steps, gaps and edges can be quite a challenge for passengers at times. Barrier free boarding and exiting of rail vehicles makes the lives of passengers with physical disabilities or limited mobility much easier, and is also particularly convenient when travelling with heavy bags or lots of luggage.
Chicago’s new light rail vehicles will offer precisely this convenience, as they will be fitted with an intelligent hydraulic level control system from Liebherr. This outstanding feature is able to adjust the level of the vehicle floor to exactly that of the platform. No easy task for the system, considering that a full vehicle can carry a total weight of up to 36 tonnes on the tracks. In addition, the platform heights differ from station to station. The vehicle load can also have a spreading width of up to ten tonnes. This loading condition has the effect of compressing the vehicle springs - designed as steel compression springs - more or less, i.e. the carriage is higher or lower.
In order to be able to precisely adjust the floor height to that of the platform, not only it is important to know the height position of the vehicle, but it is also important to determine the different heights of the platforms. Position sensors are installed on the vehicle for this purpose.
When the carriage arrives at the train station, the sensors detect the platform height. Based on this height measurement, Liebherr’s level control system activates four hydraulic actuators per carriage, each of which pulls six tonnes of steel springs together between the carriage body and chassis to lower the vehicle until the exit edge exactly matches the height of the platform.
After all passengers have got on or off barrier-free and thus comfortably, the doors then close and the hydraulic cylinders release the steel springs. The springs move the carriage back to its starting position and it can leave the station.
Similar systems from Liebherr-Transportation Systems have been operating reliably for many years in various cities in North America and, every day, make the life easier for many people.
