Abstract:This paper describes an observational study at a rail control post to measure workload weak-resilience-signals (WRS). A weak resilience signal indicates a possible degradation of a system's resilience, which is defined as the ability of a complex socio-technical system to cope with unexpected and unforeseen disruptions. A method, based upon a WRS framework, introduces a new metric, Stretch, to measure the signals. Stretch is a subjective or an objective reaction of the system to an external cluster-event, and is an operationalization of variables in an earlier Stress-Strain model. The Stretch-ratio between the subjective and objective Stretch are used to identify workload WRS. WRSs identified during real-time operation revealed obstacles that influence the resilience state and enabled actions to anticipate and mitigate changes, to maintain the resilience of the system.