How does the narrator describe the machinery Jack drives on the farm? Why is this image so powerful? How does it compare to the usual image associated with farm equipment?

The farm equipment is described as "indifferent, murderous machinery" by the narrator. By using this description, the machinery is given human characteristics: indifference, murderous. This is in stark conflict with how we usually think of farm equipment, as it is traditionally part of growing, nurturing and harvesting food with which we are fed and cared for.