What is a "Hagglund Drive"??

This is a stacker/reclaimer bucket wheel at Hay Point and Dalrymple Bay coal terminal in Central Queensland (Mackay). The terminal has dozens of these bucket wheels which stack the coal when it arrives from the coal mines aout 400 km inland and then reclaims the coal and sends it along the conveyor system to the awaiting ships to go straight off to China. They do about 90 Million tons a year here and are busy doubling the output at this one location. At any one time there are up to 70 ships awaiting loading. The Hagglunds drive is the hydraulic motor that turns the bucket wheel and runs the hydraulics network on the machine. They stand about 20 stories high and we climbed all over the thing on walkways which are grids of expanded metal. Quite fun when the wind is howling and you have seemingly nothing below you but the ground.