Three railway guns were built, using guns from the sunken battleship "Imperatritsa Mariya", which had been lost to a magazine explosion in Sevastopol harbor in October 1916. They were used in the Soviet-Finnish war in 1939-1940. In June–December 1941 they took part in the defense of the Soviet naval base on Finland's Hanko Peninsula (Rus. Gangut/ Гангут). They were disabled by Soviet seamen when the base was evacuated, and were later restored by Finnish specialists using guns from the withdrawn Russian battleship "Imperator Aleksandr III". After the war these were handed over to the Soviet Union, which were maintained in operational condition until 1991. Withdrawn from service in 1999, they were the last Obukhov pieces still operational in the world.