Earlier quoted context omitted.
Are these new trains different from the Siemens locomotives that Amtrak have been using in the Midwest for the last ~10 years? I don’t recall ever seeing anything on the back of those trains.
I wonder if it's like the double-decker passenger cars used for Metra in Chicago. These trains never change direction (like Amtrak) but just run forward (IIRC) into the city and reverse back out to the suburbs. The car on the end has a small cab where the engineer sits and controls the train when it is running reversed. From the outside the difference between that and a passenger car is pretty subtle.
Like the CTA (and the South Shore) trains - every single pair could be be the lead. They all have a spot for a driver (engineer?)