Pravoberezhnaya Line (Russian: Правобере́жная линия),(literally - Right Coast line) is a line of the Saint Petersburg Metro. Opened in 1985, it is the shortest line in the system with the stations featuring a modern design. Since 1994, it has been officially designated "Line 4," but the original name is still often used in informal context.
The line originally opened to provide access from the centre for the new residential areas in the eastern part of city, along the right bank of the Neva River. However, delays in the construction of the future Fruzenskaya-Primorskaya Line (Line 5), compelled the metro officials to temporarily link the already completed northern part of the Line 5 (starting from Sadovaya) to Pravoberezhnaya Line, as they felt that it was better to have a single connected line rather than two unconnected ones. From that point on, the line expanded northward, as per original plans of Line 5 expansion.
On March 7, 2009, Spasskaya station was completed, creating the city's first three-way transfer and it officially became the new terminal for Line 4. As per the original plan, all Line 4 stations north of Dostoyevskaya were absorbed into the recently opened Kupchinsko-Primorskaya Line.
The line is served by the Vyborgskoe (№ 6) depot, and has 42 six-carriage trains assigned to it. Some of them are 81-717/714 trains from the 1980s, while others are the 81-540.2/541.2, .5, and .8 modifications from the 2000s.
Over the coming years, there will be an expansion into the west to Kamenka. In the east there are plans to expand one station further, to Narodnaya, after which there will be a new depot called the Pravoberezhnoye depot.