After cutting back the speed of the Beijing to Shanghai bullet train following a deadly crash, China is set to again make it one of the world's fastest.
New generation trains will service the route starting next month, making the 1250-kilometre journey from the capital to Shanghai in just 4 hours, 30 minutes.
The latest trains were unveiled in June and have a top speed of 400 kilometres per hour, according to the official Xinhua News Agency.
China first ran trains at 350 kilometres per hour in August 2008, but cut speeds back to 250-300 kilometres per hour in 2011 following a two-train collision near the city of Wenzhou that killed 40 people and injured 191.
China has laid more than 20,000 kilometres of high-speed rail, with a target of adding another 10,000 kilometres by 2020.
China has spent an estimated $US360 billion ($A454 billion) on high-speed rail, building by far the largest network in the world.
The fastest train in the world is Shanghai's MagLev airport train, though its route was built only as a demonstration for the magnetic levitation ('MagLev') technology.
The train can reach a top speed of 431 kilometres per hour, but reaches that speed for just a few seconds on its seven-minute journey between Shanghai's Pudong district and the city's international airport.
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