From Zelda Dungeon Wiki
Spirit Tracks. Link must first safely transport the Anouki, Noko, to Wellspring Station in the Snow Realm. Once he has done so, Noko will spend some time preparing and creating the ice in the spring's fresh and clean waters. When he is finished, he offers it to Link. If Link constantly persists him to haggle, the hero can receive the ice at no cost at all. Before Link can transport the ice anywhere, he'll need a Freight Car.