To be fair, That was a test run, where the locomotives and infra where specially prepared and did take some damage. This was a long way from operating at 320km/h every day - and today there is a 10% safety Margin, so tgvs have to be able to run at 352km/h without special prep or damage in order to be allowed to run at 320km/h during normal operation.

For comparison, a tgv test run in 2007 got up to 575km/h on fancy new track, also with some prep but no damage, but operating at this speed would make little economic sense at this point.

https://en.wikipedia.org/wiki/TGV_world_speed_record