I've also traveled Amtrak though not with children. I am afraid to fly so if I need to be somewhere its either by car or train. As Lilly said, Amtrak has the nice trains then they also have the eqaul to the city bus train

The nice trains are generally double deckers and the seats in them are huge and comfy. They recline back and foot rests. I love going up to the observation deck and just watching the countryside. Its so peaceful. I enjoy traveling by train the most as long as I get one of the "good" trains.