Talk:Expansive working

Important technological development in the history of Steam power. It's the step between Watt's separate condenser and Trevithick's high-pressure Pen-y-darren locomotive. Steam's own pressure is used to power the piston, rather than merely displacing the atmosphere and then condensing this to have atmospheric pressure perform the work. Andy Dingley (talk) 18:13, 3 December 2008 (UTC)