The first taxis appeared in August 1994, there are still few in Ulaanbaatar. They must have on their rear window a stamp "MGL". The habit is to sign a private car, which can take you where you want, in exchange of a small financial charge (with the risks that this may, of course).  
To get to the steppe, a 4X4 vehicle rental with driver is essential. You must contact a travel agency. There is no possibility of renting a 4X4 without drivers (almost no indication is given on the road, 4X4 and Russian jeeps have no assistance direction). In addition, archaeological and cultural sites are not marked or shown. 
Mongolia has 1815 km of railways, including the main line that crosses the country from north to south. It takes 5 days to link Moscow to Ulaanbaatar; and one and a half day more for the trip Ulaanbaatarr/Peking. Schedules are subject to change according to seasons. 
The MIAT, is national airway company, which conducts flights to Beijing, Khukh khot (Inner Mongolia), Berlin, and Frankfurt with a stopover in Moscow, also to Siberia, Japan and Korea, for international routes.  Air China, Aeroflot, Korean Air and Turkish Airline do also regular flights and charters.