Magnetic Levitation Train Hits 310 MPH

So when is a train not a train and a ground-effect aircraft instead?

When it is guided (restricted) by a rail?

When it derives its support from aerodynamic effects? This one is supported against gravity by magnetic levitation, and would work just fine in a vacuum. It wouldn't need the elongated snout or smooth surfaces, just an enclosure for any contents not compatible with vacuum, like passengers, livestock,etc., so it might gain even more efficiency than eliminating the air drag would imply. A wheeled train, likewise, would still be a train even if it reached this speed, as long as it did not shift to aerodynamic support at a lower speed.

Although still slower than the record breaking TGV which is a conventionally guided train.