After previously 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 4.5 hours, about half an hour faster than the current minimum. The test will pave the way for a new schedule starting mid-September. The ticket prices will not change.

Connecting the Chinese capital with its major financial and trade hub, the Beijing-Shanghai high-speed railway is one of the busiest in the country, carrying over 100 million passengers a year.

"The Fuxing was designed and manufactured in China, led by the China Railway Corporation. They hold the complete intellectual property rights of the new bullet trains - electric multiple units (EMU)- which have reached the world's most advanced levels," said He Huawu of the China Academy of Engineering.

The Fuxing (meaning rejuvenation), is a substantial upgrade on the Hexie, or Harmony trains. The Fuxing is more spacious and energy-efficient, with a longer life expectancy and better reliability.

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.

The new EMU has completed 600,000 kilometres of running assessment and increased the design life to 30 years from 20, according to He. The Fuxing has a monitoring system that slows the train in case of emergency or abnormal conditions. Telemetry allows a control centre to monitor the train in real time.

China had laid more than 22,000 kilometres of high-speed rail network by the end of last year, or about 60 percent of the world's total, with a target of adding another 10,000 kilometres by 2020. China has spent an estimated US$360 billion on high-speed rail, building by far the largest network in the world.

Several countries, including Indonesia, Russia and India, have bought bullet trains from China.

Did you know:

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.