Abstract: The present invention relates to a rail and trolley apparatus having a trolley movable along a horizontally supported rail assembly for use as a fall protection or other load supporting system. The trolley is provided with pairs of wheels arranged to engage opposing bearing surfaces in each of two channels provided in the rail assembly. Each bearing surface has a central portion and two side portions shaped to fit flush against a curved edge surface of each wheel. This allows the wheels to bear against the surfaces in multiple directions, thereby allowing rolling motion of the trolley along the rail assembly as well as loading of the trolley in any direction not parallel to said motion. As a result, the apparatus can be oriented at any angle about a longitudinal axis thereof during installation, adding to the versatility and adaptability of the apparatus.