reciprocating steam engine definition
reciprocating steam engine means equipment that is driven by steam acting on a piston causing the piston to move, and includes an expanding (steam) reciprocating engine;
reciprocating steam engine means any steam plant where the steam acts upon a piston under pressure where this action of the steam causes the piston to move, but does not include an expanding (steam) reciprocating engine with any piston diameter of 250 millimetres or less;