At the beginning of the nineties, the first tank cars with a so-called “articulated tank” were built. The design of the boiler was such that the two halves of the boiler sloped towards the center by 3°. For this reason, the contents of the tank, mainly mineral oil products, flow out almost completely without any further aids. Since the vehicles, which are of lightweight steel construction, are suitable for higher speeds, they were soon procured by other companies throughout Europe. These wagons can be found as P (=private) wagons in the stock of all European railroad companies.