Answer:
The transportation system in Mongolia consists of a network of railways, roads, waterways, and airports.
Railways
The Trans-Mongolian Railway connects the Trans-Siberian Railway from Ulan Ude in Russia to Erenhot and Beijing in China through the capital Ulaanbaatar. The Mongolian section of this line runs for 1110 km.[1] A spur line connects Darkhan to the copper mines of Erdenet; another spur line connects Ulaanbaatar with the coal mines of Baganuur.
A separate railway line is in the east of the country between Choibalsan and the Trans-Siberian at Borzya; however, that line is closed to passengers beyond the Mongolian town of Chuluunkhoroot.[2] For domestic transport, daily trains run from Ulaanbaatar to Darkhan, Sukhbaatar, and Erdenet, as well as Zamyn-Üüd, Choir and Sainshand. Mongolia uses the 1,520 mm (4 ft 11+27⁄32 in) (Russian gauge) track system. The total length of the system 1,810 km.[3] In 2007, rail transport carried 93% of Mongolian freight and 43% of passenger turnover (in tons*km and passenger*km, respectively).[4]