The term 'in operation' is used to describe something that is currently functioning or ACTIVE. AFOOT, going, ALIVE, RUNNING, and ACTIVE are all words that can be used to describe something that is in operation. AFOOT means to be on foot or walking, going means to be in motion, ALIVE means to be living or existing, RUNNING means to be in motion, and ACTIVE means to be engaged in action. All of these words can be used to describe something that is currently in operation.