Definition of "vaping"

These [putting feet on seats and leaving rubbish behind] are officially among the worst habits revealed by staff working on Northern's trains and at stations. Other bugbears include playing music through loudspeakers, not giving way to passengers getting off the train and actually illegal activities such as fare evasion and vaping in enclosed spaces. The list of misdeeds was released by the operator on March 3 to coincide with Employee Appreciation Day.

2023 March 22, “Stop & Examine”, in RAIL, number 979, page 71