High-speed champion | International Railway Journal

"The problem with placing the pantograph on the roof is that it vibrates a lot when the train is operating at high-speed," Orellano says. "The carbody's flat plate roof effectively vibrates like a drum. In older high-speed trains power cars were situated at either end so no-one was sitting below the pantograph. But in today's trains passengers are seated throughout so this has become more of a problem and is something we wanted to address."

The solution adopted for the Frecciarossa 1000 is to mount the pantograph directly to the sidewall of the carbody with the stiffness of the carbody and the curvature of the sidewall working to reduce the vibrations and as a result noise. In addition when the pantograph is not being used it is stored flat, again minimising vibrations and any impact on aerodynamics.

The only picture I found, from the pantograph diagnostics supplier, unfortunately doesn't say much (no isolators and mounting points on the carbody shown):

At any rate, when it comes to the acoustic optimisation of pantographs, European manufacturers have a long way to go to catch up with Japanese counterparts:

(Series 500)

(Fastech360 prototype; also see noise test with/without noise screens)

(E5 series)

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