Vice President Biden used a trip to 30th Street Station on Thursday to tout Amtrak's newest locomotive as an engine of the economy and a savior of middle-class jobs.

The first of 70 new electric locomotives will begin revenue service Friday in Boston, pulling Amtrak coaches on the Northeast Corridor. Amtrak is spending $466 million on the new 125-m.p.h. locomotives, being built by the rail systems division of Siemens Industry Inc. in Sacramento, Calif.

The new "Cities Sprinter" locomotives will replace models that are 25 to 35 years old. They eventually will power all Northeast Regional trains between Boston and Washington, and also will operate on the Keystone Corridor between Harrisburg, Philadelphia and New York.

Though the locomotives will not have higher top speeds than the ones they are replacing, faster acceleration and better reliability may allow Amtrak to reduce travel times between Northeast cities, Amtrak president Joe Boardman said Thursday.

Biden, accompanied by Transportation Secretary Anthony Foxx, got a tour of one of the new locomotives from veteran Amtrak engineer Richard Stolnis, of West Goshen, and Amtrak's chief of operations, Christopher Jagodzinski.

"I'm ready to roll," Biden said before taking a right-hand seat in the cab and grabbing one of the controls.

Later, in a speech to about 400 workers and political and civic leaders in the station's waiting room, Biden called for more federal spending on infrastructure, especially rail projects, to improve transportation and provide good-paying jobs.

"This is how we used to grow America," the vice president said, citing the supply chain of 69 companies in 23 states that contributed to the new locomotives. Warning that "the middle class is shrinking," he said good-paying manufacturing jobs such as the ones involved in the locomotive's production were crucial to the nation's prosperity.

"This locomotive represents a heck of a lot more than just getting from Point A to Point B," Biden said.

Michael Cahill, president of Siemens Rail Systems, said the new locomotives may help rejuvenate a domestic rail industry in the United States, with suppliers throughout the country.

Tony Coscia, Amtrak's board chairman, said, "This is very much the beginning" of rail upgrades that will start to "reverse the tide of underinvestment in our railroads."

"We're hopeful this begins a steady flow of new investment to allow us to better serve our customers," Coscia said.