The On-board Fare applies between 2 Belgian train stations.
The ticket is issued without the "On-board Fare Supplement" when departing from Maastricht, Maastricht Randwyck, Eijsden, Roosendaal, Aachen, Lille and all Luxembourg stations.
If there is no ticket office (open) and there is no ticket dispenser (or it is out of order for a prolonged period of time), the surcharge of the On-board Fare will not be applied. The train conductor's ticketing system is able to recognise these cases through regular automated synchronisations. If the surcharge was applied nevertheless (temporary problems are not recognized by the train conductor's ticketing system), you can contact Customer Services.