It's not unusual to see pet carriers stashed under seats on airline flights.

But until now pets - except service dogs - were forbidden from riding the rails on Amtrak.

This week Amtrak and the Illinois Department of Transportation announced they are teaming up in a pilot program to let travelers bring their pets along on two trains out of Chicago.

The six-month test ride beginning May 5 will allow passengers traveling between Chicago and Quincy on the Illinois Zephyr and Carl Sandburg trains.

"Amtrak is supportive of accommodating pets on trains, and through direct collaboration with the Illinois Department of Transportation and a working group led by U.S. Rep. Jeff Denham of California, we are optimistic a plan can be reached to address the needs and concerns of all our passengers," said Amtrak president and CEO Joe Boardman in a statement.

The proposal was made to amtrak by the Illinois after passengers requested the service. The ride is only 4 1/2 hours so it made a good trial run, said Amtrak spokesman Mark Magliari. He said Amtrak and Illinois DoT  will review the experiment late this year to get reaction, see what could be done better and whether the surcharge is a reasonable.

Reservations are required and a surcharge of $25 will be assessed for travel. Dogs or cats up to 20 pounds each will be accepted in carriers such as those used in airplane cabins and placed at the feet and under the seat of each pet owner. Owners must provide proof of vaccinations.

A federal bill introduced by U.S. Rep. Denham last year would require Amtrak to allow pets,