Holy cow, Scotty. How does one lift a 300 lb weight to put it on the tractor? My little factory Kubota weights are 55 lbs each. 10" by 3.5" by 3ft is one heavy heck of a weight. I can readily believe the 1000 lb estimate but just never saw a tractor suitcase weight that big. Maybe it was a trunk instead of a suitcase !?
I have no idea how you'd lift one of those weights. Except that you wouldn't without using another machine just like it.
Of course if you are a commercial machinery guy you might have a yard full of these yellow machines.
But you've put your finger on it....the thing that really stands out between utility tractor or TLB and a commercial duty machine like the JD310 is that the parts and pieces on the commercial machines are just hugely massive. The HP isn't all that different, both worlds run the same hydraulic pressures, and they have the same controls - so the stresses iin the parts are bigger but still understandable.
The big difference is in the way they are built. The shear size of the parts, of things like axles, backhoe pivots, loader pins, and bucket wall thickness, metal for steps, just everything. Even cotter pins are too big to bend with pliers, they must hammer the legs over. I've no idea how to undo one. See photo below.....
The radiator on the 310 has enough steel on the sides alone that I doubt a person could lift it out by himself. Taking a leaky cylinder off to rebuild it is easy - exactly the same procedure as with any tractor - but does require a small crane to lift it into place.
The front end suitcase weights are one more example of this extreme overbuilding for commercial duty that dwarfs big 100+ hp tractors, or Kubotas own TLBs.
rScotty