Editing Ticket machine (section)

==Enforcement==
In many countries where trains and urban transport tickets operate largely on the [[proof-of-payment|honor system]] (with enforcement by roving inspectors or conductors), there are also machines in stations (or in vehicles) for validating tickets. This is for the situation where one buys a ticket in advance and decides to use it later. Usually, the ticket is time-stamped to determine its validity period. A common problem is forgetting to validate and then being fined as if one had no ticket at all. Such machines are generally not used in the United States. Nearly all American [[mass transit]] networks operating on the honor system expect their users to buy tickets immediately before use; regular riders can avoid that inconvenience by buying period passes in advance (often from the same machines that sell daily or one-time tickets). Recently, however, a handful of [[commuter rail]] systems like [[Metrolink (California)|Metrolink]] have adopted the use of validation machines for at least some ticket types.