The South Pole Traverse tractors and equipment on the annual sea ice before the trek from McMurdo Station to South Pole Station begins. The tractor train pulls sleds of cargo and fuel between the two research stations. It takes about 43 days with the traverse fully loaded to go from McMurdo at sea level to the South Pole, which is located on the polar plateau at about 9,300 feet, and about three weeks to return to McMurdo, when the traverse vehicles are pulling less material on the return trip down the Leverett Glacier.