The Э5К (E5K) is a Family of one- to four-section electric locomotives for service under 25 kV AC. The “K” in their designation indicates that they still have DC traction motors. Of more than 2,000 locomotives built, only 32 are of the basic Э5К single-section type that has one cab on each end. The 2ЭC5К consists of two sections with one cab each and makes up less than one third of all locomotives built. The most numerous variant is the 3ЭC5К that has an additional cabless section in the middle. There is also a high two-digit number of 4ЭC5К with two central sections. As each section delivers an hourly output of 3,280 kW, the 4ЭC5К reaches 13,120 kW. Although these locomotives are generally being built for freight service, the single-section variant is being used for short-distance passenger service and as a replacement for failed EMUS.