Not exactly...
The TGV that set the 357 mph/574 kph record actually was just a slightly souped-up set of locomotives pulling an otherwise relatively normal TGV trainset, running on a recently completed portion of the TGV Est line toward Germany. It did not "destroy" the trainset or the tracks by any measure, though they did retrofit the trainset back to normal TGV standards after the record run. In fact, my wife, daughter and I had the privilege of riding on the very first paying-passenger west-bound TGV on that very line on June 10, 2007, several months after the record run ... So, yes, the line survived the test run, and I'm sure the locomotives are in service somewhere on the TGV network. Like China, the point of such high-speed tests is to explore the ultimate capability of HSR trainsets, then the "operational speeds" are set as a specific percentage of that ultimate speed capability. Not even China would "operate" a trainset with paying passengers anywhere near its ultimate speed capability... they may be able to run a train at 500 kph, but that means they are rating it for in-service operation at somewhere between 60%-80% of that speed (depending on how daring they are...). That means an operating speed of 300-400 kph... very fast, but not superhuman.
