When Sun Valley Lodge was built in 1936, Union Pacific engineers developed chair lifts to transport skiers uphill. Beginning with two modest ski slopes on Dollar Mountain and Proctor Mountain, chair lifts were used for all Sun Valley ski runs. Far superior to tow ropes and similar devices used before 1936, they quickly became popular at ski resorts everywhere. New designs were adopted for additional Sun Valley ski runs, but one 1936-style chair lift is still preserved 4 miles up Trail Creek from here.