Ulaanbaatar provides four major bus systems to its citizens. There is one trolley bus system running across the city, one combustion-powered grid, a bus system connecting the suburbs using elder combustion-powered busses, and private busses which operate during the evening and night hours when public busses are not available. Private busses started operating between 1995 and 1996. Most of the public busses operate between approximately 6:00 o'clock in the morning and 10:00 o'clock in the evening. Trolley busses are nicknamed yamaany täräg -- ``goat car'' for their horn-like power contactors on the roof.
The hardware consists of bussed produced in the Soviet Union (early models, now mainly used on long distance and suburb lines), busses produced in Hungary and Czechoslovakia (the main lines downtown), as well as recent Japanese and Korean donated busses (mid-1990s). The older suburb busses are usually painted in a orange-tinted yellow while the ``classical'' downtown bus lines sport models with a red lower half and a grayish-white upper half. The recently donated Japanese busses are blue and white while the Korean busses are painted in a subdued green. Busses are generally entered from the rear door; the conductor sells tickets there, and only then the passenger is allowed to exit through the middle and front doors.