Acknowledging the possible impacts of the location of a vertical handrail on the accessibility of wheelchair passengers, this study explores different dimensions of the vertical handrail and elements of the internal space of a metro carriage and how they can impact the behaviour of passengers. For this purpose, simulation scenarios have been developed with different configurations of the location of the vertical handrail, which includes variables such as the number of passengers boarding and alighting and the type of relationship that exists between them. In this way, participants have been recruited for the simulation in a controlled environment, using a mock-up with characteristics and dimensions representing the space inside a metro carriage. The results show that the current location, that is, in the centre of the carriage, affects the accessibility of wheelchair users. Similarly, it has been observed that placing the handrail on one side of the train has positive effects on the accessibility of these users since the boarding time is considerably reduced. In addition, it has been shown that the relationship between passengers who hold on to the vertical handrail has an impact on the accessibility of wheelchair users. If passengers holding the handrail know each other, they will use less space inside the metro, and therefore, the boarding time is reduced. Finally, a series of recommendations have been proposed for future research, for example, carrying out new simulations with a more significant number of passengers, considering other types of disabilities.