Perceived accessibility refers to individuals’ subjective perception of how easy it is to reach destinations using a specific mode of transport. As such, understanding the effect of perceived accessibility on travel behavior is essential for creating transport systems and urban environments that are efficient, equitable, and sustainable. This study develops a new integrated model by combining the Norm Activation Model (NAM), the Theory of Planned Behavior (TPB), perceived risk, and perceived accessibility. This enhanced model offers a comprehensive understanding of the factors influencing individuals’ intentions to switch to urban train systems. Additionally, the moderating effects of perceived accessibility on the link between personal, contextual factors and switching intention are also explored. The model developed is tested using data obtained from a sample of 535 individuals in Hanoi, Vietnam. This is particularly important because more research in low- and middle-income countries (LMICs) is needed to address the sustainability challenges these nations face due to their dependency on motorized private transport. The findings show that subjective norms have the strongest effect on the intention, followed by personal norms, attitude, and perceived accessibility. This study also confirms the moderating role of perceived accessibility on the link between attitude and switching intention, while the other hypotheses regarding the moderating effects of perceived accessibility are not supported by the findings. These insights aim to inform policymakers and public transport authorities in developing targeted strategies to promote sustainable urban mobility in Vietnam.