A track light assembly includes a low-voltage track. A light module comprises an elongated thermally conductive housing fitted over the track. The housing may also surround the track. The housing preferably forms an elongated channel. An elongated printed circuit board (PCB) is mounted on the thermally conductive housing and carries a plurality of clusters of light emitting diodes (LED's) distributed over the PCB surface. An elongated lens is fitted over the PCB and LED clusters. A track adapter attached to an end portion of the track includes electrically conductive contacts for electrically coupling the conductors in the track housing with contacts on the printed circuit board. Thus, a cool running, elongated, linear light module is provided which is adjustably placeable along the length of the track.