The federal government plans to loan Amtrak about $563 million to buy 70 locomotives to run along the busy Northeast and Keystone corridors, allowing improvements in service between Washington and other cities, and in Pennsylvania.

Amtrak announced the purchase of the engines last fall.

The loan is being issued through a Federal Railroad Administration financing program and will also pay for upgrades to maintenance plants and the purchase of spare parts.

The program “is a model of how we can leverage federal dollars to spur private investment and build up the economy,” said Federal Railroad Administrator Joseph C. Szabo. “It provides steady, affordable financing for major rail construction and expansion projects, and best of all, it comes at zero cost to the taxpayer.”

The Department of Transportation said in a statement that Amtrak’s purchase of the new locomotives would create 250 manufacturing jobs in California, Georgia and Ohio. The electric locomotives will be manufactured by Siemens Industry USA.

Amtrak said the locomotives are expected to begin operating in 2013 and will replace models that have been in service for 20 to 30 years. The agency also announced plans last year to buy 130 new rail cars. Amtrak plans to replace and expand its entire fleet over the next 30 years.

“Record numbers of passengers are riding Amtrak trains across our national network of intercity routes,” Amtrak CEO Joseph Boardman said in a statement. “To better serve our customers, we are implementing a fleet replacement and renewal plan to improve the reliability and performance of our equipment. “

According to the FRA, the Railroad Rehabilitation and Improvement Financing (RRIF) program provides loans and loan guarantees, which cannot be used for operating expenses. The statute creating the program requires the agency receiving the loan to pay interest and a “credit-risk” premium. Repayments are required to begin no later than six years after the loan funds are disbursed.

The loan to Amtrak is the largest ever provided through the program, officials said. In the past, sizable loans have been made to the Denver Union Station Project Authority ($155 million in fiscal 2010); Virginia Railway Express ($72.5 million in 2006); the Dakota Minnesota & Eastern Railroad ($233.6 million in 2004); and Amtrak ($100 million in 2002).

Amtrak celebrated its 40th anniversary this year and has faced questions about its role in the future of rail transportation. Critics have questioned its financial viability. Amtrak received a $1.48 billion federal subsidy this year.

The railroad also needs to replace aging infrastructure, such as bridges, tunnels and power substations, while also accommodating future demand. It has a $117 billion vision for creating a high-speed rail network on the East Coast and last year named its first vice president for high-speed rail.

House Republicans, however, have proposed privatizing the high-speed rail effort. House Transportation Committee Chairman John L. Mica (R-Fla.) has condemned Amtrak as having “one of the most dismal records on earth” and has derided it as a “Soviet-style” rail system.

Boardman told a House committee this month that he believes the legislation could hinder development of high-speed rail, at a cost of time and money that the nation cannot afford.

The Obama administration announced in May that Amtrak would receive $450 million in the most recent round of awards for federal high-speed rail funding. Amtrak has said that money will be used to upgrade service between Washington and New York.