Beijing's Line 4 subway line suspended operation in the rush hours on Monday morning due to signal failure.

The signal system failure occurred at around 7 am. Passengers were trapped in the train for more than one hour before the train moved slowly to the nearest station.

Beijing MTR corporation Limited, the operator of Line 4, told Xinhua that the service would be resumed soon.

Subway broadcasting said there was a signal system failure and advised passengers to take others means of transport such as public buses Interchange services were closed.

One picutre taken by Xinhua correspondent shows screen of one door of the train was smashed.

The corp has asked bus companies to help tranship its passengers.

Passengers queued up dozens of meters long at the entrances of the line's stop at the Beijing South Railway Station. Taxis lined up for several hundred meters near the stop to pick up people.

"I had to transfer to three subway lines to go to the downtown," said Yan Yu, a student of Tsinghua University, "The failure delayed me for over 40 minutes."

The Line 4 line's suspension made other subway lines, such as Line 2, 5, and 10, even more crowded. The intervals were much longer than in normal time.

The line, which runs runs 50 kilometers with 35 stations through Beijing from south to north, is one of the busiest in the capital. It started operation in 2009 and transports more than one million each day.

Beijing, with nearly 20.7 million people, has 14 subway lines carrying over 8.5 million passengers on an average day, according to the Beijing Subway Company.