NEWARK, N.J. — Amtrak has unveiled the first of 70 new locomotives at a plant in Sacramento, Calif., marking what it hopes will be a new era of better reliability, streamlined maintenance and more energy efficiency.

The new engines could be viewed as emblematic of the improving financial health of Amtrak, which has long been dependent on subsidies from an often reluctant Congress.

More than 31 million passengers rode Amtrak in the 2012 fiscal year, generating a record $2.02 billion in ticket revenue.

Amtrak says it will be able to pay back a $466 million federal loan for the locomotives over 25 years using net profits from the Northeast Corridor line, where ridership hit a record high last year for the ninth time in 10 years.

Amtrak President Joseph Boardman said the new locomotives “will help power the economic future of the Northeast region.”