What is it? It's a farm tractor. Powered by a 450-hp, 6 cylinder, 912 cu.in. Cummins turbocharged diesel, the STX 450 features a set of “mini-tracks” rather than wheels at each corner of the machine. STX 450 operators claim this unique drive system offers the flotation of tracks with the smoother ride of having four separate ground contact points. When new it looked something like this.