After Lomonosov had already had two different diesel locomotives with electric power transmission built, he also wanted to have a third locomotive built with a different type of power transmission for comparison. The hydrostatic transmission that was actually planned was not yet ready for use. The result was the first and to this day the only large diesel locomotive in history with a mechanical gearbox. It went into operation as Ю^m005 (Yu^m005) and was renamed Э^мх3 (Ye ^mkh3).

The chassis consisted of five axles driven by coupling rods and a one-axle and two-axle bogie at each end. The engine came from MAN and was the same as in the Э^эл2. Here, however, it was designed to be reversible, since the transmission did not have a reverse gear. It had three gears that were shifted via a magnetically operated friction clutch.

Sectional drawing with dimensions

The Railway Mechanical Engineer

Although the locomotive achieved a very high level of efficiency of just over 30 percent, the power transmission was not without problems. In addition to jerky loads on the clutches, there were also broken gear wheels. Engine power was soon reduced from 1,200 to 1,050 hp. But even this did not solve the problems, so that the locomotive was soon decommissioned and the diesel-electric competitors prevailed.

The first diesel locomotives were already being built in the Soviet Union in the 1920s, but these were only built as prototypes or in very small numbers. When the production of the Э^эл was stopped after 46 examples in 1941, no more diesel locomotives were built in the country. ALCO and Baldwin locomotives were soon ordered in the USA, with ALCO's RSD-1 prevailing. Of the 70 pieces sent to the Soviet Union, 68 actually arrived and some continued to serve until the 1980s. After the end of the war, the decision was made to build own locomotives based on the RSD-1 as soon as the locomotive factory in Charkiv was rebuilt. The production of the engine using new production methods presented a challenge, but finally the first locomotive of the series initially designated ТЭ1-20 (TE1-20) was delivered in 1947. The designation was made up of “diesel-electric number 1” and the axle load of around 20 tonnes. Later the 20 was omitted from the designation.

Generally speaking, the ТЭ1 corresponded to the RSD-1, which was in service in the Soviet Union as Д^a. The engine was essentially the same as the ALCO 539T and, like this, delivered 1,000 hp. The other assemblies were mostly adopted with minimal changes, but first converted to the metric system and thus deviated by a few millimeters from the American parts. Not only in general construction, but also in optical details, the Soviet locomotive corresponded almost completely to its prototype. This meant a wide driver's cab with a barrel-shaped roof at one end of the locomotive, followed by a narrower, long and short body respectively. The existing American-made locomotives were gradually retrofitted with assemblies based on the metric system as part of maintenance work and were thus adapted to the ТЭ1.

The diesel locomotives were often used in regions where the water supply for steam locomotives was difficult. Some were also used in the greater Moscow area or for shunting, and by 1950 almost 300 examples had been built. The ТЭ5 was built in small numbers as a variant for extremely cold climates. The driver's cab was extended with a longer housing, which protected the engine, including the turbocharger, and the battery from the cold. To test the use of coal in diesel engines, 16 examples were converted to gas generator locomotives ТЭ1^Г and dismantled again after the end of the trials. The shunting locomotive ТЭМ1 followed only eight years after the end of production of the ТЭ1, whose developments with a similar appearance are still being built today. The direct successor to the ТЭ1 was the ТЭ2, which used almost the same technology but consisted of two sections.

The ТЭ3 was developed as a derivative of the ТЭ2, which was the first mass-produced diesel locomotive developed in the Soviet Union. The centerpiece was the new 2D100 engine, which was an opposed-piston diesel engine with ten cylinders and 20 pistons. It was again a two-section locomotive, but due to the heavier and twice as powerful engines, each section now stood on two three-axle bogies. 

The two-section locomotives were designed in such a way that each section could also be used independently. Many assemblies were still the same as the ТЭ1 and ТЭ2, so still based on the original ALCO design. The basic appearance corresponded to the ТЭ2, but later locomotives received a raised cab.

Since the test runs showed good results and the power was now sufficient to replace the most powerful steam locomotives, the decision was made to discontinue the production of steam locomotives. To cover the demand, the production of the ТЭ3 was started in two large plants and from 1963 Lugansk was added. A total of 6,808 double units were built by 1973.

In order to achieve a total output of 6,000 hp, some locomotives were converted to three sections. As soon as new locomotives with 3,000 hp per section became available, they were rebuilt to two sections. For passenger trains, the ТЭ7 was based on the ТЭ3, which reached 140 km/h. The last ТЭ3 were used in Russia in freight transport until 2003. In other CIS countries, they could also be found in use in industry for a longer period of time.

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.

2ТЭ10М-2207 in November 2016 near Chelyabinsk

XTReme-93

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.

The ТУ4 was created for narrow-gauge railways that had a particularly low axle load. These included peat and forest railways, which were normally built in the 750 mm gauge typical of the Soviet Union. Some locomotives were built for the Cape Gauge used on Kamchatka. In the period from 1961 to 1972 more than 3,200 were built in the Kambarka machine factory. Directly after the end of the production of the ТУ4, the production of the ТУ6А was started, which later partially replaced it.