A structural health monitoring system comprising: a drive system of an escalator or moving walk comprising: a first drive member; a second drive member operationally connected to the first drive member; and a tension member operationally connecting the first drive member to the second drive member;at least one sensor configured to monitor a characteristic of at least one of the first drive member and the second drive member; a processor in communication with the at least one sensor and configured to determine if the structural health of the tension member is compromised based on the monitored characteristic, the processor further configured to perform a safety response action when the structural health of the tension member is determined to be compromised; and at least one additional sensor configured to monitor a characteristic of the other of the first drive member and the second drive member; wherein the processor is configured to monitor a transfer function between the first and second drive members (32, 38) to determine if the structural health of the tension member is compromised; wherein the processor is configured to compute an estimate of the transfer function using signal averaging of signals received from the at least one sensor and the at least one additional sensor; and wherein the processor is configured to employ frequency domain curve fitting to compensate for noise in the system. a drive system of an escalator or moving walk comprising: a first drive member; a second drive member operationally connected to the first drive member; and a first drive member; a second drive member operationally connected to the first drive member; and a tension member operationally connecting the first drive member to the second drive member;at least one sensor configured to monitor a characteristic of at least one of the first drive member and the second drive member; a processor in communication with the at least one sensor and configured to determine if the structural health of the tension member is compromised based on the monitored characteristic, the processor further configured to perform a safety response action when the structural health of the tension member is determined to be compromised; and at least one additional sensor configured to monitor a characteristic of the other of the first drive member and the second drive member; wherein the processor is configured to monitor a transfer function between the first and second drive members (32, 38) to determine if the structural health of the tension member is compromised; wherein the processor is configured to compute an estimate of the transfer function using signal averaging of signals received from the at least one sensor and the at least one additional sensor; and wherein the processor is configured to employ frequency domain curve fitting to compensate for noise in the system. wherein the processor is configured to compute an estimate of the transfer function using signal averaging of signals received from the at least one sensor and the at least one additional sensor; and wherein the processor is configured to employ frequency domain curve fitting to compensate for noise in the system.