to the outboard side of the pontoon the opposite front end of the pontoon is provided with an idler shaft assembly 170 comprising an idler shaft 172 with sprockets 174 176 178 secured thereto the shaft is supported at both ends by pillow blocks similar to those described above fig2 shows details of the tracks 180 that when looped around the pontoons are guided by the lower and upper channels 128 129 and the drive shaft and idler shaft sprockets each track assembly 180 comprises plural identical endless chains 182 and a plurality of transverse cleats 184 affixed to alternate links thereof each of the cleats may comprise a metal u section open outwardly as shown in fig2 which provides good traction in mud and mire we prefer however to use t shaped cleats 186 one of which is shown in detail in fig5 the generous fillets 188 between the legs of the t of at least an inch radius render the cleat self cleaning this design avoids the substantial accumulation of mud that can detract from buoyancy with other designs fig4 shows the cab assembly 10 reinstalled upon the amphibious buggy assembly note the original hydraulic motors 20 and lines 22 for transferring fluid to and from the cab 39 s hydraulic pump.