Train driving as a control task is one-dimensional, yet very complex. This combination highlights certain problems in our understanding of skilled action. Investigations involving behavioural observations, plus interviews with over 200 drivers and inspectors, showed that the drivers utilise more information from outside the cab than is usually thought. The relevant variables were identified. The limitations to the driver's possible knowledge of the changing state of the system ahead of him lead the study to the goal-directed, purposive nature of his skill. What exactly docs he have to carry in his head to achieve the observed successes in time-keeping and safety? Consideration is given to the form of internal representations of his outside world. Quasi-mathematical operations to solve time/distance trajectory equations are suggested. Enactive, rather than verbalised, storage of information is discussed. Some practical consequences for training and equipment design are drawn in conclusion. © 1979 Taylor & Francis Group, LLC.
