This, and a lack of access to the sea, has meant that Bhutan has not been able to benefit from significant trading of its produce. Bhutan has no railways, though Indian Railways plans to link southern Bhutan to its vast network under an agreement signed in January 2005. Bhutan and India signed a 'free trade' accord in 2008, which additionally allowed Bhutanese imports and exports from third markets to transit India without tariffs. Bhutan had trade relations with the Tibet Autonomous Region of China until 1960, when it closed its border with China after an influx of refugees.