Soviet Railways series ТЭ3 (TE3)

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.