I was too young to appreciate the drink then (or is it than?
what will become of Waterloo International Terminal?
We took Eurostar from Paris soon after it came into service. Back then, the train slowed down to a paltry 60kmh or something like that once it was in the UK, running on the same tracks with the rickety BR carriages with their brown-stained windows.
The really impressive thing is that in the Chunnel, voltage and track gauge (width) changes but neither was perceptible. Also, one's ears don't pop as the train enters the tunnel.