On August 12, there was a large-scale delay in the high-speed railway.
Someone found a news story about an information leak from 4 months ago, other answers pointed out that the reason was that the signal frequency band was interfered.
The news shows that a company in Shanghai disclosed a large amount of confidential data of China's railway to a western company with close ties with the intelligence department in order to seek high profits.
This is definitely bad news, and there is no doubt that this is a test for the West to sabotage Chinese transportation.