Background The occurrences of occupational stress and sleep disorders are closely related. As a high-risk group of occupational stress, the sleep quality of locomotive engineers is of great significance for road traffic safety.

Objective To explore the direction and degree of occupational stress affecting the sleep quality among locomotive engineers, and to analyze potential mediating and moderating roles of response strategy and overcommitment in the relationship.

Methods From July 1st to July 31st, 2022, a total of 6219 locomotive engineers from three locomotive depots of China Railway Lanzhou Group Corporation were selected. We conducted an online survey on occupational stress, overcommitment, response strategy and sleep quality using the Effort-Reward Imbalance, Personal Resources Questionnaire, and Pittsburgh Sleep Quality Index. Single factor analysis and correlation analysis were conducted using SPSS 25.0 software, mediation and moderation models were constructed using the Process V3.3 macro program plugin, and Harman's single factor test was used for common method bias testing.

Results A total of 6219 questionnaires were distributed, and 5738 valid questionnaires were collected, with an effective response rate of 92.27%. The average locomotive engineers' occupational stress score (1.22±0.29), overcommitment score (16.38±3.55), response strategy score (50.00±10.00), and sleep quality score (11.51±3.95) were calculated. The Pearson correlation analysis results showed that occupational stress was positively correlated with overcommitment and sleep quality (r=0.435, 0.321, P<0.01), and negatively correlated with response strategy (r=−0.286, P<0.01); overcommitment was positively correlated with sleep quality (r=0.367, P<0.01), and negatively correlated with response strategy (r=−0.210, P<0.01); there was a negative correlation between response strategy and sleep quality (r=−0.244, P<0.01). Occupational stress positively associated with sleep quality in locomotive engineers (b=3.658, t=21.177, P<0.001); response strategy exhibited a partial mediating role between occupational stress and sleep quality, with an effect size of 0.581, accounting for 15.88% of the total effect; overcommitment presented a significant moderating effect in the first half of the mediating process of "occupational stress-response strategy-sleep quality" (P<0.001).

Conclusion Occupational stress has an impact on the sleep quality of locomotive engineers through the mediating effect of response strategy, and the first half of this mediating pathway is moderated by overcommitment.