The Kalininsko-Solntsevskaya line is a line of the Moscow Metro, currently consisting of two separate parts. It was opened as the eastwards Kalininskaya line in 1979, with the first stations of the western Solntsevsky radius opening in 2014. Presently there are 8 stations on the eastern section and 14 on the western section. The two parts are planned to be joined after 2023. To distinguish the 2 sections, the newer west section is identified as the Line 8A or Solntsevskaya Line.

The Moscow Metro is a metro system serving the Russian capital of Moscow as well as the neighbouring cities of Krasnogorsk, Reutov, Lyubertsy and Kotelniki in Moscow Oblast. Opened in 1935 with one 11-kilometre (6.8 mi) line and 13 stations, it was the first underground railway system in the Soviet Union.