On large mine sites these dollies are a must. For saving time and wear on the on the excavator. They used similar dollies in Kuwait and Saudi Arabia for moving their oil drill rigs Saving weeks of tear down and re assembly when moving from one bore site to the next. Back in the 1980s we moved drilling rigs after skidding the rig away from the hole, two gin pole trucks would be driven or backed two under the center of the substructure laying the derrick down with the crown resting on a structure mounted on a 3rd truck, then we drove the couple 100 yards or few miles to the next place we were going to drill another well.