Displaying films from travelling underground train

摘要

A device and a procedure for displaying films from a travelling underground train is described. At present, it is not possible to recognise information from a travelling underground train with a glance out of the window. Because of the high travelling speed of the train, the information eludes the observation of the human eye. The device consists of one or two flash tubes which are mounted to the sides of each window outside the train. These illuminate individual pictures of a film sequence mounted on the tunnel wall with momentary flashes of light. The flash synchronisation happens through a control unit which receives the pulse through a laser beam sampling of a control line.