Introduction: Metro driving is one of the newest jobs in Iran. Due to the lack of studies about train drivers’ workload, there is no comprehensive information about factors that effect workload. This study aimed at analyzing the factors that may effect driver workload, in order to recommend control measures.

Methods: In this mixed method study, data generation was done through field observations, document reviews, individual interviews, focus group interviews, and focus group discussions. In order to perform field data collection, the institute for occupational ergonomics and CCD Design and Ergonomics Ltd’s developed tools were used. Directed content analysis was used for qualitative data analysis.

Results: Overall, 65 factors were extracted as the factors that may effect driver workload. The extracted factors were drawn on a fishbone diagram, over 8 categories, including management, supervision and organizational climate, infrastructure, job design, journey, and environmental as distal factors and time pressure, information exchanges, and individual factors as proximal factors.

Conclusions: Some of the distal factors are the nature of an urban transport system, so the only amendment is compensatory programs, and some of them could be resolved by long-term plans. Workload of train drivers could be reduced with a focus on the proximal factors in the short-term, and the distal factors in the long-term.