BEIJING, Nov. 27 (Xinhua) -- China's high-speed rail network in operation totaled 7,735 km at the end of October, ranking it first in the world in terms of the size of its high-speed infrastructure, said an official from the Ministry of Railways on Tuesday.

The country has made a series of technological breakthroughs in constructing high-speed railways and in other major fields such as heavy-duty and high-latitude rail transport, the unidentified official said on the sidelines of Modern Railways 2012, an international railway exhibition hosted by the ministry and opened on Tuesday in Beijing.

At the exhibition, the country's two biggest train manufacturers -- China CSR Corp. Ltd. and China CNR both displayed new exhibits. China CSR showcased its test trains that can travel at over 500 km per hour, and China CNR exhibited its self-developed fast intercity trains -- CRH3A.

A total of 263 companies from 16 countries and regions including the United States, Germany and France participated in the exhibition.

China aims to create a high-speed railway backbone featuring four east-west lines and four north-south lines by the end of 2015, under a five-year plan on China's transport system approved by the State Council, China's cabinet.

The country's total length of high-speed railway is expected to reach about 18,000 km by 2015.