It runs in a general north-south direction parallel to the Danube on the Pest side, roughly following Váci út south from Újpest to the city center, then following the route of Üllői út southeast to Kőbánya-Kispest.

Operation started with Ev3 carriages, made by Mytishchi Factory (later known as Metrowagonmash) in 1976, expanded to 81-717.2/714.2 trains, built by the same manufacturer, in 1980.

[1] Line M3 runs in a north-south direction (more exactly, from north-northeast to southeast) through the city and connects several populous microraion with the downtown.

Some trains were prone to burning or smoking issues, but this had caused neither fatalities nor serious injuries so far.

The municipal government requested EU funds to finance the reconstruction of the underground infrastructure (tunnels and stations), and the national government guaranteed that it would provide additional financing in case insufficient EU funds were obtained.

On 4 September 2017 contracts for reconstructing the tunnel and stations of the northern section (Dózsa György út – Újpest-Központ) were signed.

[13] In response, Tarlós promised modular AC units would be installed on the trains and the government agreed to make all 20 stations accessible.