Amtrak also tested the X2000 tilt train, and everybody agrees that it was the inspiration for the Acela Express which came about eight years later. The Acela Express, while it still runs today, has been a technical disaster from the start, as nearly all of the engineering lessons gleaned from the X2000 testing were ignored. The X2000, however, is superb, and one of my regrets this trip was that I didn't get a chance to ride it.