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
1991 Crimean sovereignty referendum 1991 Crimean sovereignty referendum A referendum on sovereignty was held in the Crimean Oblast of the Ukrainian SSR on 20 January 1991 two months before the 1991 All-Union referendum. Voters were asked whether they wanted to re-establish the Crimean Autonomous Soviet Socialist Republic, which had been abolished in 1945. The proposal was approved by 94% of voters. The Crimean ASSR was originally created in 1921, as part of the Russian SFSR in the Soviet Union. Crimea was invaded by Nazi Germany during World War II, and when the region was reclaimed by the USSR in 1944, the Crimean Tatars, Armenians,