Texas Sunset is correct in that Amtrak may only ask 1) if the animal is a service animal, and 2) what service the animal is trained to perform. Comfort animals are explicitly NOT allowed. It can be a dog, cat, guide horse, or whatever. It is unfortunate that there are people out there who are willing to abuse the system, which in the end will only make it more difficult for the legitimately disabled who require a trained animal to travel with them.