This study examines predictors of railway commuters' changes to departure time choice. Specifically, we sought to understand the impact of pre-departure information about in-carriage crowding on train choice behavior. We present the results of an online experiment, multiple-choice task, and a survey of UK rail commuters who regularly travel on crowded trains. Our findings show that most respondents are highly sensitive to crowding on trains. That notwithstanding, we identify a group of commuters who are free from constraints but do not use their flexibility to switch. This finding leads us to suggest further research into the decision-making processes of this specific sub-group of passengers to maximize the potential of personalized real-time and predictive provision of crowdedness information. Our study contributes insights relevant to practitioners grappling with innovative information provision to encourage operationally desirable behavior change among regular commuters.