For many years we at Saab Scania have comprehensively studied the characteristics of different solutions for a steam automotive system. Since 1968 we have entirely devoted our time to a system using water as a working medium. We also use a piston engine without gearbox or clutch.The R & D work has been concentrated on the critical components. Problems of common engineering character, such as cranking mechanism etc., have been dealt with in a very limited way. Progress of the development work can be reported when it comes to compactness. An almost complete method has been developed for the cooling system. To some degree improvements have been made regarding the steam generation system and the expander. Recently it has been possible to make a fairly good estimate of production costs. These indicate almost equal costs compared with the conventional power system.