Arguments for the importance of contextual factors in understanding human performance have been made extremely persuasively in the context of the process control industries. This paper puts these arguments into the context of the train driving task, drawing on an extensive analysis of driver performance with the Automatic Warning System (AWS). The paper summarises a number of constructs from applied psychological research thought to be important in understanding train driver performance. A 'situational model' is offered as a framework for investigating driver performance. The model emphasises the importance of understanding the state of driver cognition at a specific time ('Now') in a specific situation and a specific context. (c) 2005 Elsevier Ltd. All rights reserved.