A track assembly comprising an endless track trained about a sprocket and forward and aft sets of idler wheels. A plurality of apertures at the sprocket engage drive lugs that project from an interior track surface. Longitudinal stabilizer arms restrain the idler wheel axles, idler wheels, sprocket support rollers, sprocket and track against lateral movement and tension the track. Overlapping seals are formed at the idler wheels and/or sprocket support rollers. Alternative sprockets having cutouts or pockets that capture different drive lug configurations are also disclosed along with several alternative track tensioning assemblies that rotate in an eccentric fashion to tension the track.