The development and production of vehicles in Croatia started in 1951 by a tram prototype. This was followed by several key mile-stones: trolley bus, diode type locomotive, thyristor type locomotive, thyristorisation of diode type locomotives, chopper trams, transistor tram, all the way to the transistor electric multiple unit (EMU) in 2009. The development and production of electrical equipment for submarines started in 1970 by developing and producing the main and auxiliary propulsion for a large submarine. This was followed by the development and production of the auxiliary and main propulsion for a small submarine. Written by Professor Zvonko Benčić, University of Zagreb.