Devices for detecting the occupied state or free state of a track section and method for operating such devices

A device detects an occupied state or a free state of a track section and has a transmitter for feeding a transmission signal in the form of an alternating voltage into the running rails of the track section and at least one receiver for receiving a reception signal which is brought about by a transmission of the transmission signal via the running rails of the track section. In order to be able to detect faults in the device, in particular cable faults, particularly reliably and at the same time cost-effectively, the device accordingly is configured to determine a phase shift between the transmission signal and the reception signal. A method for operating such a device is further disclosed.