China’s bullet trains are struggling to operate at their promised speeds. The top speed of all trains is being decreased from about 218 mph to 186 mph. The cause of those safety issues? Shoddy workmanship and allegations of corruption. Chinese media reported allegations that some contractors might have used lower-quality ash that had been mixed with other substances. Couple this with the massive debt incurred to build the railway, the high price to ride and the lack of people riding as a result, and it looks like the system is in serious trouble.”]
Source: https://gizmodo.com/china-slows-down-bullet-trains-because-theyre-unsafe-5796672