DED - Dragging Equipment Detection
A variety of objects are typically secured at or near the underside of a train and they may become loose or partially detached from the train in some situations. For example, a broken bogie axle, the vibration of the train travelling along the track may cause an air hose, a pipe or another object to drag beneath the train. Subsequently this dragging equipment can damage the track and present a hazard to infrastructure equipment, e.g. train stop, points, and crossings and even derailment of the train. There is also a potential safety problem which could result in derailment. Trains drivers may continue to drive their trains and are unaware of the situation that the trains are causing extensive damage to the infrastructure.
Furthermore, axles which have the potential to seize as a result of bad bearings and lack of maintenance might cause the wheels to de-rail without the train driver knowing this. This will damage the track and infrastructure, and require expensive track repair.