An access system for passenger boarding of a vehicle is provided. The access system includes a frame mounted to the vehicle. A transfer member is movably mounted in the frame. The transfer member is movable with respect to the frame between a stowed position and a deployed position with respect to the vehicle. A first drive assembly is positioned along a first side of the frame and a second drive assembly is positioned along a second side of the frame. A linking member extends between and connects the first drive assembly with the second drive assembly. There is further provided a control assembly that is engageable to at least one of the linking member, the first drive assembly, and the second drive assembly to allow operator selection of a manual or automatic mode for deploying and stowing the transfer member.