Froze...Should you prefer to take a trailer, I suggest you research the train schedule and find the older style trains...They do not have the storage spaces near the doors, but instead have a baggage car..THink there are still some non-surfliner style,older cars left...
With the baggage compartment, you can just put you bike in storage, lock it to a post and and leave it feeling secured..In the baggage car,there was no need for a bike box..Not when I used the older style trains.
Ask the local Amtrak ticket agent, he/she can tell you if the train has a baggage car...If you do not need a baggage car( trailer,tandem) new new style train car works just fine..As long as you secure a bike hook before the area gets cluttered with bags.. Should not be allowed.