A frame system for supporting an associated vehicle for transport within an existing transportable structure having longitudinally extending side structures. The frame system has a transverse supporting frame supported by two vertical posts located one at each end of the supporting frame. Each post has an attachment for securing the top and bottom of the post at a plurality of locations along the length of the associated side structure and the supporting frame is raiseable with or without a vehicle loaded thereon and once raised is fixable to the posts at a chosen location for transport within the transportable structure. Each end of the support frame has an end plate for sliding up and down an inwardly facing surface on the adjacent vertical post as it is raised and lowered. At least one of the end plates has a telescopic connection with the remainder of the support frame.