Allis-Chalmers model G tractor, 1948-1955.
© Science Museum / Science & Society Picture Library
This tractor was intended for market gardeners or 'truck' farmers as the Americans called them. The tools (not shown) were attached to a frame (toolbar) carried between the wheels, which could be raised and lowered. It was intended for use mainly with crops planted in rows, the clear view that the operator had of the implement in relation to the crop being a great help in this regard. David Brown, the British manufacturer, bought out a similar machine but the tools were raised and lowered by compresed air.