Development of Workload Tools for Signalling
Network Rail
background
Historically there have not been any mental workload assessment tools developed specifically for the railway industry. Tools created by the likes of NASA had been used but had never provided a perfect fit with the mix of field assessment and predictive modelling required on the UK railways. Network Rail wanted more railway specific tools so that (a) any terms used in an assessment scale would have meaning to the railway staff and (b) the tools dealt with the complex dynamics of the signalling environment with concurrent tasks being performed.
project
Network Rail had worked with the Insitute of Occupational Ergonomics at Nottingham University to develop a conceptual framework for railway workload assessment and had developed an initial tool set. For this project, CCD and IOE collaborated to undertake a set of simulator and field tests to validate the tools for future live use.
The tools under evaluation were the Integrated Workload Scale (IWS) and Timeline Assessment.
implementation
CCD conducted a series of simulator trials to examine the sensitivity of the tools, the validity of the tools as a measure of workload, the intrusiveness of the tools on the primary tasks, the usability of the tools and the practicality of recording with the tools. This set of trials led to a number of modifications to the tools and an identification of the next steps.
The second phase of the project delivered a set of field trials in a number of representative signal boxes.
outcomes
The trials conducted by CCD led to a number of improvements in the tools and the eventual recommendation that the tools were suitable for use in the field and that Network Rail should have confidence that workload was being suitably assessed with them.
This formative work by CCD and IOE has led to a suite of tools being widely adopted by the Ergonomics National Specialist Team at Network Rail and are still in extensive use today.