The Passenger Rail Reform and Investment Act passed on a vote of 316-101 in the U.S. House of Representatives last month. The bill funds rail transportation for the next few years, and now has some changes meant to encourage use of trains.
At least one car per train would be allowed to be designated for passengers who want to bring along a domesticated dog or cat to transport in the same manner as a carry-on bag. Currently, only service animals are allowed on Amtrak, while this legislation would allow a family pet under 20 lbs. The passenger would pay for the pet, and there is a 750-mile distance restriction for how far a passenger can bring their pet.
sources
http://www.bloomberg.com/news/articles/2015-03-04/fido-and-fluffy-may-be-your-amtrak-seatmates-under-house-measure
http://www.npr.org/blogs/thetwo-way/2015/03/04/390841422/house-approves-amtrak-funding-rewrites-rules-to-allow-furry-riders
https://www.facebook.com/pages/Allow-pets-on-Amtrak/142734622415506
http://www.travelpulse.com/news/car-rental-and-rail/congress-files-bill-that-would-require-amtrak-to-adopt-pet-policy.html