Since the ICE-1 running gear has been replaced in the wake of the Eschede disaster, I guess difficult to tell inside. Except if you're in the restaurant car, or a driving trailer (the latter only ICE-2). But outside, the swing doors for the couplers on the noses identify the ICE-2 (the headlights had the be moved up too, resulting in a less sleek appearance).

_{*Lunatic*, n.
One whose delusions are out of fashion.}