Stepped up business travel in the Northeast helped Amtrak boost ridership by nearly 6 percent to a record 28.7 million passengers in the fiscal year ended Sept. 30, the railroad said Monday.

Amtrak, the only long-haul passenger rail service in the United States, also said year-over-year ticket revenue rose by 9 percent to a record $1.7 billion for the period that began last Oct. 1.

All of Amtrak’s lines experienced growth as the railroad competed more heavily with air travel in its flagship Boston-New York-Washington market.

Northeast traffic overall was up 4 percent, helped by more business travel, Amtrak said. Ridership on the Acela, Amtrak’s fastest train and the service most geared for business travel, was up more than 6.5 percent.

Amtrak ridership and service have improved over the past several years with the help of increased U.S. government subsidies and political support in Washington for maintaining rail service outside the heavily traveled Northeast.

The rail line said it is working with states to expand existing service and establish new routes. It is also buying new rail cars and taking other steps to improve its aging infrastructure, especially in the Northeast.