Open loop transit system with a backend system

A backend system of an open loop transit system, includes at least one billing module configured to bill a completed trip at least based on a received start data set, a received end data set and a fixed preset tariff datum, wherein the start data set and the end data set each contains the same medium identification reference determined from the electronic medium identification of a ticket medium detected by at least one validator device and at least one transport information datum, at least one dynamic tariff determination module configured to determine a current tariff datum based on a requested trip datum and at least one tariff criterion, at least one output module configured to output the current tariff datum, and at least one storage module configured to store a journey data set containing the requested trip datum, the outputted current tariff datum and a medium identification reference.