This is a heavy duty rack with two rails. You must place in an area with access to both sides as if you only load up one side, it will tip over. With the second rail, there is a lot of extra weight to move this rack around. These are the heaviest of any collapsible type racks. Also, even thought there are two rails, it cannot hold double the amount of weight. It still can hold the same amount as the heavy duty single rail model due to the weakest link being the wheels.