The Bolshaya Koltsevaya line, known in English as the Big Circle Line (BCL), designated Line 11 and 11A is a rapid transit line of the Moscow Metro. It is the third circle line on the system, running outside of the existing circle Koltsevaya line and interlocking with Moscow Central Circle, with a temporary branch to Delovoy Tsentr station in Moscow International Business Center.

Under a staged construction program, work to build the BCL began in November 2011 and was completed in 2022. The first section opened in 2018, followed in December 2021 by the longest section of the Moscow Metro to enter service at one time, running for 20km with 10 stations.

BCL now serves a total of 31 stations, 24 providing interchange with existing or planned routes of the metro and suburban railway networks. The final sections of the BCL to open included Maryina Roscha - Sokolniki to the north of the city center, serving one intermediate station at Rizhskaya.

The new trains are also equipped with a passenger information system that features line diagram displays above the doors and interactive route planners. Passenger comfort is enhanced through improved sound insulation and adaptive lighting which changes intensity according to the time of day.

According to the Wikipedia/ railjournal