Rail & Public Transport

Mental workload of train signallers

ProRail, the Dutch infrastructure manager, aims at an optimal mental workload for train signallers. Train signallers complained about their workload being either too high or too low, also there were issues with the differences in the level of mental workload on different workplaces.

Intergo was asked to investigate the mental workload of train signallers on several workplaces to get insight in the level of mental workload and possible measures for optimization.


First of all, Intergo organized a kick-off with a project group in which characteristics and possible bottlenecks were determined for each workplace. This way the current situation was carefully assessed.
Then, the mental workload was evaluated using three different approaches:

  1. The objective workload was assessed using Task WeighingTM. This instrument is developed by Intergo and includes multiple aspects of the train signallers job. Task WeighingTM uses several objective characteristics of the train signallers job and therefore gives insight in which taskelements cause high(er) workload.
  2. The subjective workload was assessed using the Integrated Workload Scale (IWS). IWS was developed especially for train signallers. IWS gives insight in the level of workload perceived by the train signaller.
  3.  A yearly questionaire was used to get insight in multiple aspects of the working organisation and working conditions of the train signallers. Analysing this questionaire can give insight and support in the results of Task Weighing™ and IWS


The results showed that the mental workload of the train signallers can reach high levels, especially during and right after rush hour. Both Task Weighing™ and IWS showed these results. The high workload can continue for several hours, but there are also periods of low workload. A low workload isn’t desirable as well, and the transition from low workload to high workload is also demanding.
In a specific case Intergo advised support by another train signaller especially during rush hour and calamities. Also results of the investigation show that a good work schedule, the possibility to take over from each other during breaks and good supervision play a role in the workload experienced by the train signaller. In another case it was advised to optimize working processes together with other stakeholders, like train operating companies.

With these results and key points it was possible for ProRail to optimize the mental workload on the specific workplaces and gear all activities to one another.