| In 1959 the Berne-Loetschberg-Simplon (BLS) modified and permanently coupled two of the pioneer Bo-Bo locomotives introduced in 1944 and eventually produced five sets of twin locomotives producing about 6,000 horsepower. Used to haul 900 ton trains up the 2.8 percent grades at about 50 mph. Used for freight and passenger work, sometimes double-headed. |