The Re 4/4 II is the largest locomotive series in Switzerland, with 277 delivered units. It was built and put into service over a period of 21 years from 1964 to 1985. The first series, consisting of 49 locomotives (11107–11155), was delivered between January 1967 and November 1968. Weighing 80 tons, it has a power output of 4,700 kW and a top speed of 140 km/h.