under one's own steam

A reference to the operation of a steam engine: see sense 1.

• ""People come at their own risk, at their own expense, under their own steam," said Mhairi McKenzie-Robinson, chief administrator of the Fringe [Edinburgh Fringe Festival]."
• "After the event, [Steve] Jobs even briefly joined the media where Apple's new product line was being shown. He walked under his own steam, of course, easily and without any apparent discomfort. […] Whether Jobs's health is in decline or not, it's undeniable that the past five years have been the most fertile of his magnificent career."
• "I'd been wanting her to go for a long, long time, hoping she'd get up the gumption to do it under her own steam so I wouldn't have to make a scene about it."