I was the Chicago Coordinator for Trails & Rails from Dec. 2012 until July 2015... for our program that operated on the Southwest Chief between Chicago and La Plata, MO.
No, Trails & Rails programs are only presented in the lounge car. Volunteers are not allowed to make announcements train-wide -- unless it's a welcome announcement when they get on -- that goes train-wide. Those are the official rules put forth by Amtrak and the NPS. Trails & Rails used to do some train-wide announcements when the program started in 2000, but that was changed when people complained.
The only exception to the above policy is for the T&R program on #7 and #8 (Empire Builder) between Seattle and Spokane. There is no lounge car, so docents stand on the bottom level of one of the coaches and narrate train-wide, as there is no other option. They are allowed only one announcement every 10-20 minutes.
Non-Trails & Rails narrations (California State RR Museum, Collis P. Huntington RR Society, etc.) follow different rules and may narrate train-wide.
Sorry, but we have done and continue to do train-wide announcements on #19 and #20 and get very favorable response from the pax and we are a T&R program.
I think having the announcements train-wide is an intrusion. I have not been on the Crescent, so I don't know the details on that train, but two times over the Sierras on the Zephyr with the museum lecture piped throughout the train was more than either my wife or I could stand. It was awful. About 30 minutes into the second time (exact same lecture as three years earlier), I suggested we just jump from the train and hope for only minor injuries. It was moving slowly enough: it might have worked.
While I don't doubt some passengers enjoy the talks, I am also sure that some do not. They may want to read a book, watch a movie, sightsee, or take a nap. With the lectures train-wide, there is no escape. Amtrak already has announcement overload on trains between the endless dining car calls for reservations and cafe car promos. Adding train-wide history lessons makes it all that much worse.