Train controller interface design: factors influencing mental workload

Train controller workload level is important in terms of at least two outcomes: (1) the safety and efficiency of system performance-determined at the individual controller level by the quality of situation awareness, strategic planning and decision-making, and (2) controller well-being-reflected in levels of frustration, stress and satisfaction, and at the organisational level in absenteeism and/or illness. Controllers' mental workload is an important consideration in determining how much territory or traffic is allocated to a single controller. If the control system is significantly modified in some way-for example by partial automation-the effects on controller workload should be assessed, particularly in terms of required staffing level. Related issues concern possible relationships between controller workload levels and the need for formal rest breaks or limitations on shift durations or total hours worked in a week. All of the above issues were raised in the project from which data in the present paper are drawn. Present focus is on the way in which train controllers' work was analysed to determine the effects of automation, particularly its effects on the nature and level of controller workload.