i m NOT sure that "validate a ticket" means 检票.
检票 means someone checks your ticket. for example, when u r sitting in a train, which has been moving, an inspector will check everyone's ticket.
"validate a ticket" is what we must do with a machine before we take a train. we put our tickets into a little machine and this machine gonna print something on our tickets. if we dont do this, we CAN'T take any train even if we have a ticket.
anyway, this is how we take a train in france. in china, as i know, there is not a machine to validate a ticket like this. so there is no "validate a ticket" in china.
we say : 打票 if we want to say "validate a ticket"