Which railway is commonly described as the world's longest railway line?

The Trans-Siberian Railway is commonly described as the world's longest railway line.

Its classic Moscow–Vladivostok route extends for about 9,289 kilometres across Russia. Construction began in 1891 during the Russian Empire, and the main route was substantially completed by 1916.

The railway crosses the Ural Mountains and Siberia before reaching the Pacific coast. A standard journey takes about a week, although passengers can stop at cities and regions along the route.

The Trans-Siberian system includes related branches, notably routes through Mongolia and China. The name therefore refers to a network as well as the famous Moscow–Vladivostok line, and published distances can differ according to which branch or endpoint is counted.