In many European and international transit systems, "validating your ticket" means officially activating it by marking it with the current date, time, and station code. Many tickets purchased at kiosks are "generic" and do not have a specific travel time; therefore, you must insert them into a validation machine (often a small yellow or green box) before boarding the train or bus. This process prevents travelers from using the same ticket multiple times and shows the conductor that the fare has been used for your current journey. In 2026, even some online or digital tickets require "validation" via an app check-in before the train departs. Failing to validate your ticket is a common mistake that leads to heavy on-the-spot fines, sometimes exceeding €60, as ticket inspectors generally do not accept "I didn't know" as an excuse for an un-stamped ticket.