Only three weeks ago the Chicago-Louisville Kentucky Cardinal was extended to Louisville from its former terminus at Jeffersonville, Ind.

Continuing the train to Nashville may make economic sense, as the consist currently sits idle at Louisville for more than 12 hours. And that leaves plenty of time for the train to make the 181-mile run between the namesake cities of CSX's former Louisville & Nasville main line.

"The inspection trip is purely for CSX and Amtrak engineering people to evaluate the infrastructure for future passenger service," according to the Tennessee Association of Railroad Passengers.

Amtrak wouldn't say more about the train other than it will run this week and that it would be just one of many factors considered in an evaluation of Nashville service.

Officials in both states back the idea, and earlier this year Amtrak President and CEO George Warrington met with them to discuss new service. U.S. Rep. Bob Clement, D-Nashville,will be aboard the train, Tennessean newspaper of Nashville reported.

Extending the train may already be a done deal. When the Kentucky Cardinal pulled into Louisville for the first time on December 4, Acting Amtrak Intercity President Don Saunders said that an announcement regarding Nashville could come later this month.