Rail transport in the Soviet Union the Soviet Union collapsed. Twenty other stations were under construction in 1985. The country's rapid transit system was the most intensively used in the world. The Soviet Union was a pioneer in the development of the diesel locomotive to replace the steam locomotive (dieselization) on non-electrified lines. But the USSR failed to make steady progress and while they lead the United States at first, they soon fell behind and their last steam locomotives were retired about 15 years later than for the US. The first mainline diesel locomotive in the world began running in 1924 in the USSR but it
Spartakiad of Peoples of the USSR Spartakiad of Peoples of the USSR Spartakiad of Peoples of the USSR (, Spartakiada narodov SSSR) were mass multi-event competitions in the Soviet Union in 1956–1991, descendants of the 1928 All-Union Spartakiad that took place in Moscow. The competitions were conducted between constituent republics of the Soviet Union, while the Russian side was represented by three teams and included separate teams from Leningrad and Moscow. The competitions also were organized as winter and summer. There were 10 summer Spartakiads and 7 winter Spartakiads. In 1952 the Soviet Union decided to join the Olympic movement, and international Spartakiads ceased. However the