With regard to vehicles, the Finnish motor industry consists mostly of manufacturers of tractors (Valtra, formerly Valmet tractor), forest machines (f.ex. Ponsse), military vehicles (Sisu, Patria), trucks (Sisu Auto), buses and Valmet Automotive, a contract manufacturer, whose factory in Uusikaupunki produces Mercedes-Benz cars. Shipbuilding is an important industry: the world's largest cruise ships are built in Finland; also, the Finnish company Wärtsilä produces the world's largest diesel engines and has market share of 47%. In addition, Finland also produces train rolling stock.