The Lötschberg had always been in the forefront of electric locomotive development and their 4,000 h.p. Bo-Bo design, introduced in 1944, was the first of its particular type in Europe, if not in the world. Shortly afterwards in 1946, the very successful Swiss Federal Bo-Bo type was introduced and for many years undertook the working of the high speed lightweight trains over the Geneva-Zurich, Geneva-Basle and other main lines.