An apparatus comprising an elongate planar member, a number of flanges, and a number of channels at ends of the number of flanges. The elongate planar member may have a first side, a second side, and a number of holes. The first side may be opposite to the second side, wherein the first side may be capable of being secured to a track having a substantially planar surface with an array of holes. The number of flanges may extend from the second side of the elongate planar member. Each channel in the number of channels may have a bottom, a first wall, and a second wall. The first wall may have a first lip, and the second wall may have a second lip, wherein the first lip and the second lip may extend towards a centerline of an associated channel in the number of channels.