An extruded rail assembly including a first multi-channel extrusion having at least two tubular channels connected by a center rib, and having a joining end configured for joining at a predetermined angle to a joining end of a second multi-channel extrusion. The second multi-channel extrusion includes at least two tubular channels connected by a center rib, and having a joining end configured for joining at the predetermined angle to the joining end of first multi-channel extrusion. The joining ends of the first and second multi-channel extrusions are configured such that the center ribs complementarily engage as a joining surface.