Passenger transport system, comprising: a central control unit for controlling functions of the passenger transport system; a plurality of field devices (17, 17(a), 17(b), 17(c), 17(d), 17(e)), which are arranged inside the passenger transport system in a spatially distributed manner, and a bus system for transferring data between the central control unit and the field devices (17, 17(a), 17(b), 17(c), 17(d), 17(e)), each field device (17, 17(a), 17(b), 17(c), 17(d), 17(e)) being configured to output data to the central control unit and/or to another field device (17, 17(a), 17(b), 17(c), 17(d), 17(e)) via the bus system and/or the central control unit being configured to output data to at least one of the field devices (17, 17(a), 17(b), 17(c), 17(d), 17(e)) via the bus system, the passenger transport system being configured to carry out a failure detection method, in which - the field devices (17(a), 17(b), 17(c), 17(d), 17(e)) are received in a logically linked manner as in an unbranched chain configuration, - the control unit transmits a test telegram to a first field device (17(a)) in the chain configuration via the bus system at the start of a monitoring cycle and - during the monitoring cycle, in response to the relevant field device (17(a), 17(b), 17(c), 17(d), 17(e)) receiving a test telegram, each field device (17(a), 17(b), 17(c), 17(d), 17(e)) forwards the test telegram to a next field device (17(b), 17(c), 17(d), 17(e)17(b)) in the chain configuration via the bus system, until the test telegram reaches a final field device (17(e)) in the chain configuration, characterized in that - during the monitoring cycle, the control unit monitors a communication between the field devices (17(a), 17(b), 17(c), 17(d), 17(e)) occurring via the bus system, in order to detect when a field device (17(a), 17(b), 17(c), 17(d), 17(e)) does not forward the test telegram. a central control unit for controlling functions of the passenger transport system; a plurality of field devices (17, 17(a), 17(b), 17(c), 17(d), 17(e)), which are arranged inside the passenger transport system in a spatially distributed manner, and a bus system for transferring data between the central control unit and the field devices (17, 17(a), 17(b), 17(c), 17(d), 17(e)), each field device (17, 17(a), 17(b), 17(c), 17(d), 17(e)) being configured to output data to the central control unit and/or to another field device (17, 17(a), 17(b), 17(c), 17(d), 17(e)) via the bus system and/or the central control unit being configured to output data to at least one of the field devices (17, 17(a), 17(b), 17(c), 17(d), 17(e)) via the bus system, the passenger transport system being configured to carry out a failure detection method, in which - the field devices (17(a), 17(b), 17(c), 17(d), 17(e)) are received in a logically linked manner as in an unbranched chain configuration, - the control unit transmits a test telegram to a first field device (17(a)) in the chain configuration via the bus system at the start of a monitoring cycle and - during the monitoring cycle, in response to the relevant field device (17(a), 17(b), 17(c), 17(d), 17(e)) receiving a test telegram, each field device (17(a), 17(b), 17(c), 17(d), 17(e)) forwards the test telegram to a next field device (17(b), 17(c), 17(d), 17(e)17(b)) in the chain configuration via the bus system, until the test telegram reaches a final field device (17(e)) in the chain configuration, - the field devices (17(a), 17(b), 17(c), 17(d), 17(e)) are received in a logically linked manner as in an unbranched chain configuration, - the control unit transmits a test telegram to a first field device (17(a)) in the chain configuration via the bus system at the start of a monitoring cycle and - during the monitoring cycle, in response to the relevant field device (17(a), 17(b), 17(c), 17(d), 17(e)) receiving a test telegram, each field device (17(a), 17(b), 17(c), 17(d), 17(e)) forwards the test telegram to a next field device (17(b), 17(c), 17(d), 17(e)17(b)) in the chain configuration via the bus system, until the test telegram reaches a final field device (17(e)) in the chain configuration, characterized in that - during the monitoring cycle, the control unit monitors a communication between the field devices (17(a), 17(b), 17(c), 17(d), 17(e)) occurring via the bus system, in order to detect when a field device (17(a), 17(b), 17(c), 17(d), 17(e)) does not forward the test telegram. - during the monitoring cycle, the control unit monitors a communication between the field devices (17(a), 17(b), 17(c), 17(d), 17(e)) occurring via the bus system, in order to detect when a field device (17(a), 17(b), 17(c), 17(d), 17(e)) does not forward the test telegram.