Reunited!
I slept pretty well and when I awoke, I got a cup of tea and called the 800 number. After being entertained by the automated phone system, I eventually talked to a human who said something to the effect that “Checked baggage doesn’t get delivered to Boston anymore.” Nice! She told me to file a lost baggage report on their website. Did it. Then I decided to go back to sleep. Upon reawakening, I hiked over to the train station (10 minute walk) and thought I’d ask around. A more alert Amtrak employee explained what had happened. The 448 train couldn’t have a baggage car due to the splitting thing in Albany. Instead, baggage checked to Boston arrived the next morning. Good to know - would have been even better to know when I checked it in at Emeryville or at least in Chicago. I could easily have grabbed my backpack in Chicago and schlepped it onto the Boston train. There was plenty of space for another bag. Lesson learned.