It does seem that if a kitchen-klutz like myself can bake a potato in a microwave that there should be a way to offer that in a cafe car.The one restaurant job I had in college ( I lasted almost 6 weeks before being released for apparent lack of taste) we would wrap up a bunch of potatoes in foil and get them ready to bake. After they were baked I think they kept them in a warming drawer until needed.
Couldn't Amtrak contract with a local vendor somewhere to bake 'em and then have them ready for a train to pick up?
They could have a big box ready to go. Maybe a bunch of salads, too.