After 1945, the tram networks in most Polish cities relied on small, slow, and outdated
Konstal N trams. The N-class trams were intended as a temporary measure to improve the disastrous state of public transport in the aftermath of
World War II, and were in fact based on a wartime German design, but all attempts at designing a better tram in Poland ended in failure. In 1955, two
Tatra T1 trams were bought by the Warsaw Transport Authority. In 1956, these were sent to the
Konstal works in Chorzów for analysis, and formed the basis for the first Konstal prototype called
11N. The prototype was then modernized with a redesigned interior, Belgian
ACEC electrical equipment, different wheels, and transmission. In 1959, the prototype was put into production as the
13N. == Passenger service ==