The FAA is a vehicle which is designed to allow the carriage of a 9’6” high container within UK railway loading gauge W6/W6A. Carriage of these tall containers is not normally possible on “standard” UK flat wagons as the container will foul the loading gauge but these wagons achieve this end by carrying the load between the bogies. This reduces the payload per unit train length, as only 66% of the train length is effective, but it avoids the technical problems and increased maintenance costs of very small wheels. The FAA has an advantage over the Pocket Wagons since they can carry 2.5 metre wide containers, the Pocket Wagons being restricted to 8’ wide containers.