Thierry Grosjean, economy minister for the canton, was travelling by rail between Môtiers and the city of Neuchâtel last Friday when he was checked by a conductor, the local news site arcinfo.ch reported on Wednesday.
The ticket Grosjean was using was invalid because it had expired two hours earlier, the news site said.
The politician, a member of the right-of-centre Liberal party, was fined 100 francs on the spot, which he paid immediately.
“I took a return ticket from the Neuchâtel station,” Grosjean is quoted as saying by arcinfo.ch to justify what happened.
However, such tickets have not existed since 2009 when a new system was introduced for the local train service, the news site said.
Under the regulations a ticket remains valid for a period of time that depends on the number of different “zones” for which it is purchased.
The time is clearly marked on the ticket and in the case of Grosjean’s ticket it was two hours, arcinfo.ch reported.
Grosjean embarked on the return train six hours after buying the ticket.
He acknowledged feeling foolish, having ended up paying twice the normal fare in addition to the fine.
But arcoinfo.ch said that Grosjean, who reportedly does not often use public transport, added: “I am going to ask for detailed explanations from the transport company (TransN).”