Describes the dimensions for the interchangeability of seals and other wearing parts and gives also the important dimensions for: - manholes for gas tank wagons located in one end of the tank; - manholes for gas tank wagons located on the top of the tank including the arrangement of fittings; - bolted manholes for tank wagons for liquid substances located on the top of the tank; and - swing bolt manholes for tank wagons for liquid substances located on the top of the tank.