What does ‘travel with a partly valid ticket’ mean?

You will be given a ‘travel with only a partly valid ticket’ form, if you are travelling with a ticket that is valid for the entire route, but is insufficient for one of the following specific reasons.

• have a ticket for the wrong customer group (e.g. a half-price or reduced-price ticket without justification)
• have chosen the wrong mode of transport for part of a route
• max. 1 missing zone for regional transport tickets or max. 1 missing stop for national transport tickets.
• who are not in possession of a class upgrade
• who are not in possession of a route upgrade or hold a ticket for a different route (which has the same departure and destination stations or the same departure and destination zones, but another direct and similar route)