This is correct. With respect to anything Amtrak, my limited experience is that there is often a difference between what is said and what is done.

Last year I did a century (Anaheim to San Diego) where we planned to take the Amtrak back. That day, they were doing track work, so they were sending everyone departing San Diego by bus. I called them in advance and they told me "no bikes." So we made arrangements for the bikes to be hauled back by another means.

As we exited the bus from San Diego, we noticed a couple of cyclists pulling their bikes from the baggage hold in the bottom of the bus. Did they slip the driver a $20 bill? We'll never know, in all likelihood. Anyway, it was clear the "no bikes" rule was not enforced evenly.