If you move up the arrival date of the Rohr/RTG tubroliners to about 1968, they might have used Grand Central Terminal, in addition to the UAC Turbotrain, that might have orginally been purchased by the New Haven.
Either that, or maybe after the Rohr trains were used on the Adirondack, after about 1974, and you were modeling Montreal. Don't know which station Amtrak used there, about that time, but CN also had copies of the UAC Turbotrain.