What is false dowty retarder phenomenon of dowty retarder

I don't know if you have any idea about the "false dowty retarder" of dowty retarder. Let's introduce how the "false dowty retarder" of dowty retarder is.

With the rapid development of railway,dowty retarder, as an advanced speed control equipment without external energy, has been widely used in various marshalling yards and plays an important role in the safe coupling of vehicles.

However, in the practical application of dowty retarder, it is often encountered that when the vehicle passing speed exceeds the critical speed of dowty retarder, the dowty retarder does not do braking work, but the sliding oil cylinder of dowty retarder can slide up and down, which is called "false dowty retarder" phenomenon. This kind of "false dowty retarder" is not easy to be found in patrol inspection, but it seriously affects the safety of shunting operation.