Chinese President Xi Jinping has set in motion another ambitious mega-project to make secluded, mountainous Tibet more accessible.

By 2025, passenger and cargo trains will start pounding along a new 1,600-kilometer rail line that zigzags from Chengdu, capital of Sichuan province in the lowlands of the southwest, through craggy hills and scale an elevation of more than 3 kilometers to reach the Tibetan capital Lhasa, on a plateau dubbed the “roof of the world.”

Lhasa is about 3,200 meters higher than Chengdu.

Xi announced the start of the project on Wednesday in a meeting also attended by Premier Li Keqiang.

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Chinese Premier Li Keqiang inspects a construction site of the Sichuan-Tibet Railway near Lhasa in July. Photo: WeChat

Lhasa is already served by a 1,956km rail link to Xining, capital of Qinghai province, which was inaugurated in 2006 by Xi’s predecessor Hu Jintao, and since then the Tibetan capital has been connected to China’s extensive rail network.

The Qinghai-Tibet line includes the Tanggula Pass, the world’s highest point on any railway at 5,072 meters above sea level.

Lhasa, the holy city of Tibetan Buddhism with a population of just half a million, has seen an influx of tourists and worshippers from Beijing, Shanghai, Guangzhou and other centers who hop on trains equipped with oxygen outlets.

The new high-elevation electrified link from Chengdu is projected to cost 105 billion yuan (US$16 billion) to build, with preliminary construction already started from both ends.

Trains will cruise at up to 160km/h on the new shortcut through not only the slopes of the Qinghai-Tibet Plateau, but also across large expenses of permafrost, faults and swamps in tunnels or on bridges, with 34 intermediate stations and with breathtaking views guaranteed.

Two of the 14 mountains the new line will pass through are higher than 4,800-meter Mont Blanc, the highest in the Alps.

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Existing roads linking Lhasa to Chengdu wriggle through rugged terrain. Photo: Xinhua
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Track-laying work along the new railway. Photo: Xinhua

The Economist called the new railway “a colossal roller-coaster” in a 2016 report.

A Chinese government website, China Tibet News, said in 2014 that building the Sichuan-Tibet line had become “extremely urgent,” not just for developing Tibet but also to meet “the needs of national-defense-building.”

More projects are also in the pipeline with lines to connect Lhasa with Kunming in the southwestern province of Yunnan and Urumqi in Xinjiang.

Read more: Extra sausages and oxygen: PLA spoils high-altitude troops