BEIJING - China is aiming to build separate passenger and freight networks within its railway system, one of the world's busiest. It may come true on some bustling lines in 2015, when a high-speed passenger transport network is expected to become fully operational.

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

The Ministry of Railways?said?that the total milage of high-speed railway will reach some 18,000 km by then.

China's high-speed lines, which should have an average speed of over 200 km per hour, stood at 6,894 km in August, fewer than last year as a speed cut was executed after the Wenzhou accident, according to the ministry.

Railway expert Wang Mengshu said that as new high-speed lines open, transportation capacity will be released from conventional lines, which will gradually turn into freight lines.

"Putting passenger and freight on separate tracks will greatly increase traffic volume," said Wang, also an academician of the Chinese Academy of Engineering. "The plan indicates that China will continue to develop high-speed trains to address its transportation bottleneck."

The plan is long-awaited as China's high-speed railway development has been set back by the Wenzhou collision last July that left 40 dead.

The crash seriously dented China's enthusiasm for high-speed rail. China halted work on new lines and conducted nationwide safety checks. A total of 54 people, including minister-level officials, were punished following the accident. Local railway bureaus and stations have been ordered to improve train scheduling and management, as well as conduct more intensive work safety training.

A railway ministry report released in July says that signaling and lightning diffusion equipment has been checked and reinforced at more than 1,000 railway stations.

The changes were in response to the two major causes of the Wenzhou accident, management failure and faulty signaling equipment.

"With technical solutions and disciplined operation, China's high-speed railways will be safer," said Huang Qiang, chief researcher at the China Academy of Railway Sciences.

Wang said China should always bear the accident in mind and learn from past mistakes. "This will be highly important in China's further pursuit of technological innovation and advancement."

Wang held that China should persist in the high-speed railway development.

"Over the past 15 years, China has raised the speed of its conventional lines six times, leaving little room for further improvements," said Wang.

"It will be very dangerous if we continue to raise the speed of conventional lines. Therefore, we must build new dedicated passenger lines."

Passenger trains have shared the same tracks as freight trains since the creation of China's rail system. The shared railroad system has made it difficult to meet market demand on busy lines.

World Bank figures show that China has by traffic volume the world's second business freight railway and the busiest passenger railway.

Wang noted that China had only 93,000 km of railways by the end of 2011. ?"The railway mileage per capita is shorter than the length of a cigarette."

"The railway density in China is far from adequate to serve the world's second-largest economy," he said.

Ye Tan, a well-established economic commentator in China, said the creation of a high-speed network will leave more conventional lines free to carry cargo and meet market demand.

She also eyed high-speed railways as an alternative to replace the property sector to create jobs and drive China's flagging economic growth, which cooled to 7.6 percent in the second quarter, the lowest in the past three years.

While construction slowed down after the Wenzhou accident, the Chinese high-speed railway sector has seen some breakthroughs in research and development and international cooperation in past months.

In August, China's North Locomotive and Rolling Stock Corporation Limited delivered to Siemens AG a batch of high-speed train compartments worth 14.3 million U.S. dollars, marking the first such export to Europe.

In April, China South Locomotive and Rolling Stock Corporation Limited won a bid to provide high-speed trains for Hong Kong.

The trains will run on the Hong Kong section of an inter-city high-speed railway connecting Hong Kong, Shenzhen and Guangzhou. The deal marked the first time for a Chinese company to sell high-speed trains to Hong Kong.

Foreign leaders have shown interest in Chinese high-speed railway. During her visit to China in April, Thai Prime Minister Yingluck Shinawatra rode a high-speed train from Beijing to Tianjin. At the end of the 33-minute trip, traveling about 120 km, she said it is convenient and Beijing and Tianjin seem to be one city.

Thailand and China signed an agreement on strengthening railway cooperation during Yingluck's visit, according to a joint statement issued by the two governments.

Passengers are returning to China's high-speed rails. Some 52.6 million passengers traveled on the Beijing-Shanghai high-speed railway in its first year of operation, which ended on June 30. More than 144,000 passengers on average travel on the line daily.

While more major Chinese cities are getting connected with high-speed lines, a larger network is under plan to link all cities with a population of 500,000 people or greater.

According to the five-year plan, China will form a 40,000-km-long network, composed of lines with an operational speed of 160 km-plus per hour, by the end of 2015.

But it remains uncertain whether all the projects specified in the plan can be accomplished, as the Ministry of Railways, the main investor for China's rail projects, faces a heavy debt-to-asset ratio of as much as 60 percent.

The capital-strapped ministry issued a statement earlier this year inviting private investors to participate in the funding of rail projects. The ministry promised it will treat private capital and public funds equally.

Ye said private capital has been reluctant to enter the sector, as it has been plagued by poor efficiency and backward management. She has repeatedly urged for more reforms in the sector.

Wang thought the invitation lacks details. "Private capital will be very cautious about entering the railway sector unless there is a good profit distribution scheme for all parties involved."