The ТЭП70 or TEP70 is a six-axle diesel-electric passenger locomotive that is still in production after more than 50 years. Compared to the earlier ТЭП60, it has a four-stroke engine delivering 4,000 hp instead of the two-stroke with only 3,000 hp. It weighs 135 tonnes, has a top speed of 160 km/h and the basic variant has no electric train heating. In contrast to the ТЭП60, the generator of the ТЭП70 produces AC and rectifiers are being used to power the DC traction motors. To improve running characteristics, it uses Alstom quill drives. Seven prototypes were built between 1973 and 1977 and mass production of a modified variant was started in 1978. Apart from the first 20 or 30 locomotives, all are capable of multiple working, although this feature is not being used regularly.

By 2006, 576 locomotives of the original variant had been built. Back in 2002, production of a more modern variant called ТЭП70БС or TEP70BS had been started. This features micro processor control, electric train heating and is also being produced with gearing for 120 km/h for heavy trains on lines with long inclines. 374 of this variant had been produced by 2025 and production is still running. Based on this, 26 locomotives of a variant called ТЭП70У or TEP70U were produced in 2006 and 2007. These have 80 hp more and no train heating. For freight service, only twelve 2ТЭ70 or 2TE70 were built between 2004 and 2007 which are combined of two sections with one cab each.