The Polovinny tunnel is the longest tunnel of the Circum-Baikal Railway. Its length is 778.4 m (2552 ft). Unlike the other tunnels of the Circum-Baikal Railway this one is absolutely straight.
The tunnel is drilled through Polovinny Cape, one of the most beautiful spots of the railroad. The cape and the tunnel got their names thanks to the Polovinnaya River whose mouth divides the distance between the Station of Kultuk and the source of the Angara River in two equal halves.