Here's a high flat trailer with a Cat D-8 (a GHQ model). This was often loaded by dropping the front of the trailer to the ground, running the equipment onto the trailer bed, and then using the tractor's winch to pull the trailer back up to the truck's fifth wheel. During the hook-up the load was usually moved to the rear so most of the weight was over the trailer tires and then moved forward for the proper weight distribution.