Investigating the Relationship between Noise, Vibration, and Lighting with Chronic Fatigue and Occupational Stress of Metro Train Operators

Abstract

Background: The metro environment is a crucial and widely utilized component of modern transportation. Various factors significantly affect the comfort and performance of metro employees, operators, and passengers. Therefore, this study aims to investigate the relationship between noise, vibration, and lighting conditions with chronic fatigue and occupational stress among two groups of metro personnel: train operators and ticket office staff. Methods: This study employed a descriptive-analytical, cross-sectional design. The statistical population consisted of 30 metro operators and 30 urban train ticket office staff in Shiraz City, Iran. Following informed consent, participants completed the Effort-reward imbalance questionnaire (ERIQ). Noise level was evaluated using a sound level meter, while lighting levels were measured with a lux meter. Additionally, vibration was assessed according to the ISO 2631-1 standard using a calibrated vibration meter. Data were analyzed using descriptive and inferential statistical techniques in SPSS software. Findings: The sound pressure levels in both investigated areas were below the standard limit, while the vibration level in the operator’s cabin exceeded the standard exposure limit. The lighting levels were measured at 15 lux in the operator’s cabin and 320 lux in the ticket office, both of which were within the acceptable standard limits. A significant difference was observed in chronic fatigue and occupational stress between operators exposed to noise, vibration, and lighting and employees without such exposure, indicating a greater impact of these factors on metro operators. In examining occupational stress, significant differences were found between the two subscales of effort and over-commitment. The most common stress level experienced by both groups was moderate, and no participants in either group reported a high level of occupational stress. Conclusion: The levels of chronic fatigue and occupational stress among metro operators are higher, because they are directly exposed to physical stressors. Therefore, further research is warranted in this field, along with the implementation of appropriate measures to maintain the health and improve the efficiency of metro train operators © 2026, Isfahan University of Medical Sciences(IUMS). All rights reserved.