Chris, I flat out do not believe you on that story. There is no way that a Koyker 160, rated at 1500 pounds lift, is going to pick up and carry 7080 pounds. It is even less probable that it could pick up one that is over 8000 pounds. Quickly checking Koyker web site shows the largest loader they make for a 145-275 HP tractor would not be able to lift over 6000 pounds.
I also don't believe that a 3000 pound 28 hp tractor could pick up 7000 or 8000 pounds. It would require a counter weight in the 5000 pound range to keep the rear tires on the ground. Since the 3pt capacity of the Jinma 284 is 876 pounds, well that's a bit shy of what would be needed....
I also checked the weight per foot of I-beams. There are only a few that are over 100 pounds per linear foot. The heaviest I saw was 112 pounds per foot, making your 15% heavier than 7080 pound beam over 70 feet long. By the way, those are bridge girders 10" wide and 18" tall and VERY thick.
jb