The rail lines in Switzerland with their grades, tunnels, bridges, and curves are a special challenge for the locomotives that travel over them. Mastering the 240 kilometer / 150 mile Gotthard line in particular demanded extraordinarily powerful locomotives over the years. A freight locomotive, the Crocodile, became famous on this line. The largest and most powerful locomotives were however the three class Ae 8/14 electric locomotives. They were developed in the 1930s just for the demanding requirements of this steeply graded line. Each of these double locomotives had a weight of 240 metric tons. The 8 traction motors for the locomotive gave a starting tractive effort of 50 metric tons and an hourly output of 7,500 horsepower that was transmitted by the proven Buchli drive system from the Ae 4/7.