ABSTRACT
This chapter presents a conceptual framework produced for the rail industry to provide a common language and understanding of the multiple dimensions of mental workload. The framework has acted to direct the development of workload measurements capable of assessing the dimensions most relevant to railway signallers and the aspects of workload with greatest priority for Network Rail. The chapter justifies the need for and the development of the nine point integrated workload scale for signallers. It justifies the choice and development of a self-reporting integrated workload scale for the assessment of railway signaller mental workload, to meet the need for: tools to be used on- or off-line; and tools to tap operator experiences and views. Self-report of workload is widely accepted as capturing the operator's perception of workload or effort. Some authors believe that subjective ratings are the most sensitive and accurate reflection of mental workload.
