mev

No space in a rooomette. The entire dimensions are 3.5ft by 6.5ft (https://www.amtrak.com/difference-be...ette-a-bedroom). In that are two seats facing each other and above a bunk that folds down.

Logistically there will be a problem with the "can you bring it" question. When I've traveled, there is one attendant for each sleeping car. That might have 10 roomettes in one half, five or six bedrooms in the other and then downstairs an end room, a set of bathrooms/showers and some luggage space. That is their entire domain and they tend to be present when you check in, helping convert seats to beds, etc. So you can't expect to sneak on a bicycle onto such a sleeping car. I suspect most attendants would discourage/redirect you to carry the bicycle somewhere else. So we're back to the folding bicycles can probably work but something larger I wouldn't expect to bring into a sleeping car - even if technically speaking you might be able to collapse things to fit in a family bedroom...