Amtrak said earlier this week that its state-supported routes were responsible for 15.4 million of its record 31.6 million passengers in fiscal 2013, which concluded at the end of September.
Amtrak officials said the state-specific routes were vital to the future of the rail company.
"We thank these state leaders who have sent a strong message in favor of Amtrak service and the need to offer multiple mobility options for the traveling public across their regions," Amtrak CEO Joe Boardman said in a statement.
"These state-supported services are vital links in the Amtrak national network that bring value, connectivity, economic development and jobs to states and local communities," Amtrak Board of Directors Chairman Tony Coscia added.
Amtrak operates 28 state-supported routes, in addition to its regular service on the populous Northeast corridor and its long-distance trains, which are heavily subsidized because they have traditionally lost money.
The company was allowed to contract with states to increase its service offerings by the 2008 Passenger Rail Investment and Improvement Act, which also includes the authorization for Amtrak's funding from the federal government.