ZiU-9

ZiU-9, or ZIU-9 (Cyrillic: ЗиУ-9) is a Soviet (and later Russian) trolleybus. Other names for the ZiU-9 are ZiU-682 and HTI-682 (Cyrillic: ЗиУ-682 and ХТИ-682). The ZiU acronym stands for Zavod imeni Uritskogo, which is a factory named after Moisei Uritsky, the Russian revolutionary. Before 1996 this acronym was also a trademark of the vehicle manufacturer Trolza. The ZiU-9 was first built in 1966, although it was only put into mass production in 1972 and it was still assembled along with other more advanced trolleybus vehicles in the Trolza (former ZiU) factory until 2015. The total number of produced ZiU-9s exceeds 42,000 vehicles making it the most produced trolleybus in the world. In addition, many copies of ZiU-9 were made in other factories of the former Soviet bloc. The explosive development of trolleybus systems in the Soviet Union in the 1960s required a large number of trolleybuses to operate on said systems. The mainstay of the contemporary Soviet trolleybus fleet, the ZiU-5, was not sufficient for large urban passenger transfers as it was more suited for medium-size cities rather than large megapolises such as Moscow or Saint Petersburg. In addition, the ZiU-5 had an aluminium exterior, which was expensive and complicated from a technological point of view. The two doors in the ZiU-5 hull ends did not work well in overcrowded situations which were quite common in Soviet public transportation. The ZiU-9 was a quite successful attempt to solve these problems. It has one extra door compared to the ZiU-5.the middle and rear doors are wide, to allow for passenger flow. the small door at the front end of the vehicle is comfortable for the driver and for outgoing passengers. The exterior of the ZiU-9 is made of welded steel and is significantly cheaper and simpler than the exterior of the ZiU-5. The electrical equipment of the ZiU-9 had some minor differences from the ZiU-5. The power of the main motor was increased. The indirect resistor-based control system of electric current was slightly modified to deal with the increased power of the main motor.