A reporter went to the Xi'an High Speed Train Application Station in Shaanxi Province Thursday to see how the high speed trains are examined and cleaned.

In the nearly 500-meter long "high speed train maintenance workshop", all the trains stop in the long tracks. Workers check every part of the train respectively and clean both the exterior and interior of the train.

Besides examinations by eyes and hands, ultrasonic examination is also applied to high speed trains that have traveled a certain miles. Even the tiny wear in metal can be seen directly through the images and statistics.

What impressed the reporter most is that every screw cap should be marked with a line after being fastened. "If the line is found mismatched next time when we check, it means that the screw cap is loose and needs to be fastened. The examination is closely related with the safe operation of the high speed train. We must be serious, careful and maintain high standards. Even a screw cap must be checked," a worker said.