For what it is worth, on Amtrak's bicycle page - https://www.amtrak.com/bring-your-bicycle-onboard they have listings of trains under two general headings:

"Carry-on Bicycle Service" where "Bicycles must be stored in the designated racks/areas inside Coach passenger cars." and

"Trainside Checked Bicycle Service" where "Passengers are not allowed in baggage cars, so you will hand your bicycle up to an Amtrak crew member inside the baggage car when boarding and they will store and secure your bike in the bike racks."

I have used the term "roll-on/roll-off" to include both Carry-on Bicycle Service and Trainside Checked Bicycle Service. Amtrak might use the term to apply to either as here is an example from 2015 when they initiated service on the Capitol Limited - https://bikepgh.org/2015/09/15/amtra...rvice-is-live/ and you'll find the Capitol Limited in the list for Trainside Checked Bicycle Service.