Abstract
Rail signalling is typical of a complex control task where situation awareness (SA) has been thought to play a significant role. Taking into account the main theoretical positions, and through reviewing cognitive accounts of signalling, it is apparent that SA is a useful construct in describing and understanding rail signalling at both a cognitive and a system level. Development and maintenance of SA is complex, requiring much expertise and knowledge on the part of the signaller to extract and synthesise relevant information from the environment. The display and other artefacts and actors in the system also play a major role in the construction and maintenance of SA. This suggests that it is not sufficient to consider SA purely as an individual's product of knowledge. Instead, the active use of SA, such as in design, must reflect the distributed nature of the signalling environment, as found in other command and control-type domains. Rail signalling has not yet been subjected to in-depth analysis in terms of SA and has characteristics that make it distinct from other areas where SA has been analysed (e.g. air traffic control). This paper reviews the validity of SA and associated concepts to this safety-critical function, as well as highlighting some of the characteristics of SA (multiple tasks, display-based and distributed SA, role of local knowledge and expertise) that must be considered to use the construct in an operational context.