[1] Between 1992 and its closure, it was operated by Zarząd Transportu Miejskiego (ZTM), in English the Public Transport Authority (Warsaw).

[1][2] They operated from Plac Unii Lubelskiej to Warszawa Gdańska train station, and from the Łazienkowska depot to the city centre (ulica Piękna).

The first system's fleet had also included 15 French-built Vétra trolleybuses, purchased new in 1947, and 30 East German-built LOWA [de; hu] vehicles, received in 1952–53.

The national government policy at the time was that as much Polish coal as possible be exported while the oil be imported at very low prices from the USSR.

However, economic conditions made construction of the latter line impossible, and only the former, on the direct route between Warsaw and Piaseczno, was opened.

This single route, numbered 51, opened on 1 June 1983, returning trolleybus service to Warsaw.

[4] After 1989 it became apparent that the ZIU trolleybuses were in need of replacement, and that the cost of running a single line was very high.