Austrian Federal Railways class 4020

The class 4020 is an electric multiple unit developed in the seventies for the Vienna S-Bahn, but later also used on busy commuter lines in several parts of Austria. The Bundesbahn class 420 was used as an inspiration, but the 4020 has only one powered car with an output of 1,200 kW. It is being controlled by thyristor and has automatic speed control. The control car is being designated class 6020 and the center car as class 7020.

120 three-car sets were built by SGP between 1978 and 1987. The electric part came from BES, a joint venture between BBC, ELIN and Siemens. Over the years they were modernized on the interior and electronics. From 2014 they got LED headlights, but the first ones were withdrawn in 2016. Some were reactivated in 2019 due to problems with the introduction of the class 4746. More were finally withdrawn between 2020 and 2023, but many are scheduled to be used until 2030.