The Moskovsko-Petrogradskaya Line (Russian: Московско-Петроградская), is the second oldest line of the Saint Petersburg Metro, opened in 1961. It featured the first cross-platform transfer in the USSR. It was also the first metro line in Saint Petersburg to feature a unique platform type that soon became dubbed as "Horizontal Lift". The line cuts Saint Petersburg on a north-south and is generally coloured blue on Metro maps. In 2006, as an extension was opened, it became the longest line on the system.
The Tekhnologichesky Institut transfer is a cross-platform one.
The line is served by the Moskovskoe (№ 3) depot, and has 56 six-carriage trains assigned to it. Most of these are of type 81-714/717, but some are the .5 standard, built in the 1970s through the 1990s. There are also newer 81-540.1/541.1 and .9 trains running since 2000.
The line is complete as such, and the recent extension to Parnas means that in the long future no future extensions will be built. However it is very likely that some of the central stations will be receiving much needed repairs internally and externally.