The longest train journey in the world is in Russia. This should come as no real surprise, considering the absolute enormity that is Russia. The 5,778 miles (9,300 km) long Trans-Siberian Railway runs from Moscow to Vladivostok in the country’s far east. If you combine the length of the Trans-Siberian with all the other railway lines in the country, it would be able to circumnavigate the world twice!