Soviet Railways series 2ТЭ10, 3ТЭ10 and 4ТЭ10 (2TE10, 3TE10 and 4TE10)

After the introduction of the ТЭ10 (TE10) freight locomotive, it was realized that a much more powerful locomotive would be needed for the heavy trains. So a double locomotive was created by taking two ТЭ10 with only one cab each and to use them permanently coupled, what created the 2ТЭ10. They still had six axles per section and a 3,000 hp ten-cylinder opposed-piston two-stroke diesel. Compared to the use of two conventional locomotives, this saved the cost of two cabs.

After 26 ТЭ10, a total of only 19 2ТЭ10 were built starting in 1960. Mass production started with the 2ТЭ10Л (2TE10L) in 1961. This had been modified in some aspects and was built 3,192 times. The next variant was the 2ТЭ10В (2TE10V) with 1,898 pairs built from 1975. Then 3,688 2ТЭ10М (2TE10M) followed starting in 1981.

The last major variant was the 2ТЭ10У (2TE10U) that was introduced in 1989. The most important change in this variant was the revised engine of type 10Д100M2 that had some improvements in fuel efficiency. By 1996, 655 had been built, of this 100 were of the variant 2ТЭ10УT (2TE10UT). These were intended for passenger traffic and had a top speed of 120 instead of 100 km/h.

To further increase the power of the locomotives, three- and four-section variants have been built from multiple generations of the 2ТЭ10, creating the 3ТЭ10 and 4ТЭ10. The mid sections only had a rudimentary cab and could not be used to head a train by themselves. From all variants, 719 3ТЭ10 and 25 4ТЭ10 were built.

In total, more than 10,000 of all variants have been built. Most of the original 2ТЭ10 have already been retired in the eighties and were mostly replaced by basically the same locomotives in a new variant. Some of the latest variant even got new four-stroke engines in the 21st century. A number was still in service around 2020 and most likely, they will even stay in service for years to come. Depending on the current state of maintenance, these locomotives are a common sight with massive black smoke.