A detailed ready to run model of the initial design of high capacity, long wheelbase and air braked open wagons, carrying the old style coding OPEN A B (for Air Brake).
These wagons were built by BR to provide vehicles suitable for running at high speed to form a rolling stock backbone for the new air brake network of fast general merchandise freight trains, later marketed under the Speedlink banner. Through the 1970s these new opens steadily replaced the fleet of small vacuum braked wagons built in the 1950s, raising the average speed of freight trains and cutting in-transit time.