On this day in 1903 Friedrich Gehricke and Friedrich Bollmann were granted the patent for Safety Device for Railway Vehicles in Case of Derailment. U.S. Patent No. 735,239.
This invention related to the application to railway-vehicles of an appliance having for its object to prevent the vehicle from passing entirely off the rails when the wheels become derailed and to support it in such a manner as to allow of its continued travel. For this purpose there is arranged in front of or behind each pair of wheels a transverse bar adapted to come into contact with and slide upon the rails when the wheels become derailed, such bar being provided with downward extensions situated between the rails. So long as the wheels of the vehicle run upon the rails the skidding-bar is raised up to a certain height from the rails; but when the wheels are derailed the bar sinks onto the rails and at the same time the one or other downward extension comes into contact with the inner side of the corresponding rail; according to the direction in which the wheel have run off the rails. By this means the vehicle is prevented from passing entirely off the rails and can continue to travel by reasons of the skidding-bar sliding along the rails.
