Sokolnicheskaya line (until 1990 — Kirovsko-Frunzenskaya) is the first line of the Moscow metro. It connects through the center the Moscow districts of Bogorodskoye and Sokolniki with Khamovniki, Moscow State University on Vorobyovy Gory, Vernadsky Prospect, Troparyovo-Nikulino district and New Moscow. In the diagrams, it is indicated in red and a number one.
The line is 44.1 km long and has 26 stations; the duration of the trip along the entire line is 67 minutes. Sokolnicheskaya line has the largest number of operating stations in the Moscow metro (until 2019 this status was held by the Serpukhovsko-Timiryazevskaya line) and is the second longest after Arbatsko-Pokrovskaya. The average daily passenger traffic in 2016 was 962.2 thousand people.
The line has both deep and shallow sections, as well as a small open section in the area of the Preobrazhensky metro bridge and a covered ground section «Salaryevo» — «Kommunarka». In addition, the Vorobyovy Gory station is located on the Luzhnetskiy metro bridge. At all stations of the line, passengers enter and exit from the left side relative to the movement of the train.