This light metro line could be built as an extension of a northern ring metro, but also as a separate project. It is a ring line in the sense that it is at right angles to the radial routes, but it can also be described a a second east-west metro line, about 2 km south of the already planned metro line 2.
The line would start at from Warszawa Zachodnia station, west of the central area. There it would connect with the cross-city line, and with the proposed northern ring metro or northern ring S-Bahn.
From there, the line would run south-east to the Rondo Jazdy Polskiej (interchange with metro line 1, Politechnika station). Two possible alignments are shown below, the southern variant seems to be the better route.
From Rondo Jazdy Polskiej, the metro would follow the Trasa Łazienkowska, an east-west road alignment built in the 1970’s, and cross the river Vistula (Wisła). The variant shown here then follows the roads Ostrobramska and Marsa, to Warszawa Gocławek station on the line to Otwock (rail line 7).
From Warszawa Gocławek station, the line could be extended alongside or under Ulica Marsa, to Rembertów station on rail line 2. In that case it would allow interchange with all the lines of the proposed urban-regional metro network.
If the line was primarily intended as a ring line, the line could turn north after crossing the Vistula, to Warszawa Wschodnia station.