Amtrak also operates intercity buses, Amtrak Thruway, for some minor routes and when their trains are snafu'ed. I understand Thruway's bike policies are much like Bolt? Somebody fact check me on that?
I know there's a situation in a nearby city where you can book Amtrak all the way to Winston-Salem, but what actually happens is that you get off the train in High Point and switch to a bus to Winston Salem. The bus is also listed on the regional transportation website, so I don't know who actually has ownership, just that you can book as part of an Amtrak trip, or you can take it without it being part of an Amtrak trip. The bus has a front bike rack, like many city buses, that holds two bikes. But they are not reservable. If you try and book a trip to Winston-Salem via Amtrak, you can't book space for your bike. When I wanted to do that, I booked the trip to High Point and reserved a spot for my bike on the train. Then I paid the bus fare separately when I got on the train to Winston-Salem, and I put my bike on the rack. The bus didn't have any extra baggage area, as far as I remember, but that makes some sense, given that I don't think High Point nor Winston-Salem offer checked baggage service. It's all carry on, except for bikes.