But a debit card explicitly isn't a credit card, which is what's being talked about here

As the comment you've replied to says, they are limited by the line speed and their design, and design speed, is effectively the same as the latest TGV.

You're not understanding the difference between the line speed and the train's design speed. The train is capable of comparable speeds, significantly higher than the track speed

Given the simplicity of this attack and complete disregard for security by the vendor, it is likely to just be a teenager in a basement somewhere

The Acela II has a technical top speed of 189MPH.

Sounds pretty comparable to 200 mph (320 km/h) to me..

Yes... The point is the maximum design speeds of both are very similar.

Yes TGVs run operationally at much higher speeds than the Acela II but that is due to infrastructure, not the train itself. The train itself, independent of track constraints, is capable of similar speeds. I don't think there's much more worth saying on the matter.

Not when it's being used for age verification...

Steam..? The subject of the post..?

A massive nationwide network of facial recognition CCTV doesn't exist in the UK