So I decided to play with the idea of how an @Amtrak electric double decker would look like today. This is the result - Amtrak TWINDEXX.
The train is based on #Alstom (ex-Bombardier) FV-DOSTO, made for SBB. In this scenario, it has 2x first (1-stw), 1x business, 1xbus/resto and 4xcoach class (1-stw). For Europeans, 'coach' is the USA equivalent of 2nd class.
Lenght is also variable, thus it is possible to create 1xfirst+3xcoach config for commuter lines. This is a similar approach on how Twindexx is operates in Switzerland with IR and IC variants.
Trains would be named after cities on NEC, first one being the capital of course. I might make other variants with Boston, NYC, NH and Providence later - but this one is done and ready to roll out in @CitiesSkylines.
And based on feedback, here is the high entry variant: