Agriculturally redundant

A semi-derelict farm in a little valley near the Castle Hill nature reserve, odd bits of redundant machinery strewn around... I chanced upon this gem during my long Sunday run (ok, it's a Saturday... a minor detail)... the sky had been overcast, the winter bitter, but the sun peered out just at the right moment to capture this relic, part of a self-oiling bulldozer.