This product is designed to solve an important problem on the railways. When a train passes over rail points they can deflect downwards under the weight of the train. Too much movement will damage the points and will then cause delays to the train services. There is also an additional safety hazard when there is too much deflection. The Void Meter is located above a sleeper at the points, and it monitors the relative movement as the train passes by. The amount of movement is converted to an electronic signal, which is then monitored by a central computer.