Was there really a Tramway Null in Warsaw in the 1920s?

 

 

 

 

Source:   A film clip from the movie called " Przedwojenna Warszawa 1936 " which translated to "Pre War Warsaw ".  I took a clip of the movie and gave Michael Troy to convert the "15" Route Number to "0" (Null) for me.  It is very rare that a tramway system would start off it routes with a zero, but my father said that he was told in Warsaw in 1920 that in order to get to the "American Embassy" he needed to take "Tramway Null".  What do you think?