Petersburg Tram Mechanical Factory (PTMF) (Russian: Петербу́ргский трамва́йно-механи́ческий заво́д (ПТМЗ)) is one of the leading manufacturers of tramcars in Russia and the CIS-countries located in Saint Petersburg. The only plant in Russia, dealing only tram manufacturing for several decades (until 1981) was the sole supplier of rolling stock for the tram system in St.