In the early 1980s, the Soviet Union built an approximately 15 kilometers rail line from Termez in Uzbekistan to Kheyrabad in Afghanistan, crossing the Amu Darya river on the Afghanistan–Uzbekistan Friendship Bridge. In January 2010, construction began on a extension line between Afghanistan and Uzbekistan; this line is also gauge as the first one built by the Soviets. By December 2010, it began carrying construction materials for other reconstruction projects in Afghanistan. The line, which starts from Hairatan to Maulana Jalaluddin Balkhi International Airport in the northern Afghan city of Mazar-i-Sharif, was completed and is operated by Uzbekistan's national railway Uzbekiston Temir Yullari for a three-year-term until Afghanistan's own railways department takes over. The first freight services began running around August 2011. Uzbekistan has pledged in 2018 to part fund a major 657 km rail link from Mazar-i-Sharif west to Herat, which could create a route from Iran via Herat to Central Asia and potentially China. A 10-kilometer long line extends from Serhetabat in Turkmenistan to the town of Torghundi in Afghanistan. An upgrade of this Soviet-built line dating back to the 1960s, using Russian gauge, began in 2007. In April 2016, an agreement was reached for a technical feasibility study for a proposal to extend this line approximately 100 km to the city of Herat, where it could connect to the standard-gauge line to Iran that is being built. In accordance with earlier decisions, the line is likely to be standard gauge, with break of gauge at Torghundi. In April 2018 it was decided by the Turkmen government to build a railway from Galkynysh Gas Field in the direction of Afghanistan, towards Torghundi. Another rail line was opened further east in November 2016, connecting Aqina in Faryab province via Imamnazar with Atamyrat/Kerki in Turkmenistan. A planned extension to Andkhoy is under proposal. It is planned to become part of a rail corridor through northern Afghanistan, connecting it via Sheberghan to Mazar-i Sharif and on to the border with Tajikistan, although it is unclear when this will happen. Two broad gauge Pakistan Railways lines with steep gradients terminate on the border at Chaman and Torkham. In July 2010, Pakistan and Afghanistan signed a Memorandum of understanding for going ahead with the laying of rail tracks between the two countries.