And that's what it was in this case. Why Amtrak thought I should call to be told what could have been included in an email is a mystery to me. Also, Julie asked me to confirm my reservation number (which was in the email that told me to call), and then read it back to me and asked if it was correct, and then asked me if I was calling about the itinerary associated with that reservation number. Then, Julie could have said, "Oh, I see we are now offering checked baggage again." But no, Julie said to hold for an agent. All-in-all, it was rather customer-unfriendly.
On the plus side, the wait-noise all music (albeit poor quality); there were no advertisements or assurances that my call was very important. And when an agent did come on the line, she spoke English well and had a sense of humor.
Contrary to the reports in The awful experience of being on hold with Amtrak, I was not offered a call-back option. Maybe that's a package deal with announcements, advertisements, and assurances that a call is very important.
