Railway vehicles are equipped with several sensors installed in axleboxes to detect and monitor operational parameters such as speed, temperature, and vibration that provide input for several control systems, including brake and condition monitoring systems.

Railway sensors
The SKF Axletronic railway sensor solution is a flexible platform for railway vehicles that can be installed in axlebox bearing units or front covers. These axlebox bearing units, or axlebox front covers, provide several options to detect speed and operational parameters for automatic train protection (ATP), automatic train control (ATC), juridical recording units (JRU) – commonly called “black box” – brake control and condition monitoring systems.

One of the first applications was monitoring the speed for wheel slide protection (WSP) in order to avoid skidding and locking during braking. Previous designs were based mainly on inductive and optical speed sensors mounted onto the axlebox cover. This arrangement requires more space and should be considered when the railway gauge/profile cannot accommodate additional space. For this design, a toothed wheel is usually located at the end of the axle and has to be mounted separately. During installation, the air gap between the toothed wheel and the measuring equipment mounted on the housing has to be adjusted with great precision. Usually, such solutions tend to have a rather large number of components. In railway applications, as in many other fields, the trends are to reduce both the number of components and suppliers as well as the space occupied and un-sprung mass. Considering that un-sprung mass influences the dynamic load between wheel and rail as well as the wear of both, which in turn affects passenger comfort during travelling, vehicle manufacturers and railway operators are increasingly interested in compact solutions.

An SKF Axletronic sensor solution can be easily installed in both new and existing vehicles. There are two SKF Axletronic configurations available to the railway industry, depending on where the sensor should be located:
  • sensor systems installed onto the bearing seal as an integral part of the axlebox bearing unit
  • sensor systems installed within the axlebox front cover that do not interfere with the bearing unit

SKF railway solutions - SKF Axletronic

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