This is an amazing train and a beauty to look at. It won't come into service until sometime in 2022, but they're currently being tested up and down the NEC route. They can go over 150mph, although the max speed on the Boston Sprinter is 150mph, but it would still be a good train to have on the route. It will surely make the best US passanger route in tsw. (Note : these pics are not mine. They can be found on the Amtrak website). Hope you like my suggestion
I think they said they are never adding anything after the fact that was not out when the route released
Better yet combine this with HSP-46 as the Boston-Providence Into the Future or Contemporary bundle. HSP-46 has double decker cars. UK terminology Double Decker Coaches.