On 20 March 2004, an agreement between the Thai and Lao governments was signed to extend the railway to Thanaleng Railway Station in Laos, about 3.5 km (2.2 mi) from the bridge. This will be the first railway link to Laos (but not the first railway, as a short portage line once existed). The Thai government agreed to finance the line through a combination of grant and loan. Construction formally began on 19 January 2007. Test trains began running on 4 July 2008. Formal inauguration occurred on 5 March 2009.