Two high-speed rail lines were hit by extensive delays in the past few days and the system will be tested by snow and rain forecast for the coming week.

A migrant worker carries his baggage preparing to enter the Beijing Railway Station on Sunday. With the Spring Festival approaching, at least 400,000 passengers leave the capital every day. [Photo: China Daily]

More than a dozen services on the Beijing-Shanghai high-speed line were held up for as long as two hours on Saturday, just as the Lunar New Year travel rush began to reach full swing.

Some passengers at the Shanghai Hongqiao Railway Station said they heard a loud explosion and saw a flash of light at about 1:30 pm on Saturday, according to posts widely distributed on micro blogs.

The most-distributed post on Sina weibo under the username NJ Zhou Hongwei, who is identified as the general manager of Nanjing-based Renren International Travel Service, said the G121 train he was on stopped on the Beijing-Shanghai high-speed railway near Wuxi, Jiangsu province, next to a G15 train that was "caught in fire".

"It is just electrical sparks, which is normal people should not spread rumors," said the Shanghai Railway Station on its official micro blog later Saturday. The station said the G15 train had arrived safely at Shanghai Hongqiao Railway Station at 5:35 pm on Saturday.

The Ministry of Railways confirmed train services were interrupted, blaming the technical problems on the weather.

"The influence of rainy and misty weather reduced the electrical insulation on the high-voltage equipment on the roof of a Beijing-Shanghai high-speed train, causing circuit breakers on the electrical supply to jump and the high-voltage equipment on the high-speed train to switch off as a safeguard, resulting in delays to a number of trains," the ministry said.