Ukrainian Railway series ДЭ1

In the 1990s, the Ukrsalisnyzja needed to replace the Soviet electric locomotives of the ВЛ8 series in the 3 kV DC network. Since the area of application was mainly in the east of Ukraine, the electric locomotive factory in Dnipro (until 2016 Dnipropetrovsk) took over the development of a new electric locomotive for use in front of freight trains. Like the ВЛ8, it was a double locomotive consisting of two four-axle halves, with the development presumably based primarily on experience from the Soviet era. For example, the bogies and axle bearings were taken directly from the Soviet ЧС4 series, which was built by Škoda in Czechoslovakia. A new feature are computer-based diagnostic systems that show the crew all the important data on screens.

In 1995, two prototypes with a few weak points were built, followed by 38 production vehicles up to 2008, which had some improvements. In operation, it was found that even a double locomotive without appropriate anti-slip protection can easily have traction problems. Deficiencies in the maintenance of the electronic components often meant that the measured values of the diagnostic systems became inaccurate over time and that the traction motors then overheated and could be damaged or even destroyed as a result. Another disadvantage was the design of the four identical control computers with different responsibilities, which led to a lack of redundancy and, if one computer failed, to the failure of the entire locomotive.