At about 10,000 KM or just under 6,000 miles the Trans-Siberian Railway covers over 1/3 of the circumference of the Earth and is the world's longest railroad.

Czar Alexander III designed the railroad in 1891 to give Russia an accessible port on the Pacific. By 1905 the railroad was finished. indian railways

The Trans-Siberian Railway stretches from Moscow to the port city of Vladivostok on the east coast of Russia.

Below is the map of World's Longest Rail Road:


(Via: wikipedia.org)