Was the train from BER?
I'm pretty sure any train from BER airport would be covered under the 9-euro ticket. The trains not covered under the ticket are primarily ICE (inter-city high speed) and anything operated by another company (e.g. FlixTrain).
I'm pretty sure any train from BER airport would be covered under the 9-euro ticket. The trains not covered under the ticket are primarily ICE (inter-city high speed) and anything operated by another company (e.g. FlixTrain).