OBJECTIVE: Public transportation workers are exposed to higher levels of stress related to accidents, injuries, and person-under-train events when compared to other workers. This systematic review integrates the existing literature on mental health among high-risk public transportation workers to estimate the prevalence of post-traumatic stress disorder (PTSD), major depressive and anxiety symptoms following critical incidents while on duty. METHODS: This systematic review is part of a larger systematic review which examines mental health and work outcomes of individuals working in professions at high risk of critical incident exposure, i.e., high-risk professions. Articles were included if they measured the prevalence of PTSD, Major Depressive Disorder (MDD) and Anxiety Disorder (AD) in a transportation population following exposure to a major incident, for example, a person-under-a-train. RESULTS: Among the ten articles, all reported prevalence of PTSD which ranged from 0.73 to 29.9%. Four articles reported prevalence of depression among transportation workers exposed to a critical incident and prevalence outcomes ranged from 0.05 to 16.3%. Only two reported prevalence of anxiety from 1.3 to 13.9%. CONCLUSIONS: This literature reports that transportation workers are prone to involvement in traumatic accidents leading to higher rates of PTSD compared to the general population. Strategies to reduce transportation accidents and to provide transportation workers follow-up mental health support is needed for this vulnerable population.