Amtrak’s Northeast Regional, carrying travelers between D.C. and Boston, is as popular as ever. The lines to board always snake through Union Station, the prices are competitive with what airlines charge, and, Hell, the train service even recently restored the classic cheese-and-cracker tray.

But the route’s fleet is aging. Amtrak’s current locomotives on the Northeast line are between 25 and 35 years old, filled with technology that is generations behind. But this fall, the Northeast Regional will start replacing the fleet with a new model, which made its public debut yesterday.

Amtrak showed off the new locomotive, built by Siemens, at a plant in Sacramento, Calif. The new engines, which will be deployed over a three-year period, don’t offer much of an upgrade by way of rail speed, but they are far more energy efficient. Like the current fleet, the new Seimens ACS-64 locomotives are electric, but are capable of returning the power they consume back to the grid. Amtrak says in a press release that the engines’ regenerative brakes are capable of pumping up to five megawatts of power back into the catenary wires that supply its trains. In total, Amtrak estimates this upgrade could save $300 million in electric costs over 20 years.

The locomotives, nicknamed Amtrak City Sprinters, will run at top speeds of 125 miles per hour on the Northeast Regional line, and up to 110 miles per hour on the Keystone Corridor between Philadelphia and Harrisburg, Pa. Those are the top speeds of the current fleet.

In total, Amtrak will be taking delivery of 70 new locomotives, which are scheduled to be fully deployed by 2016. The purchase is valued at $466 million, financed for by Federal Rail Administration loan that will be repaid by revenue from the Northeast Corridor, the only profitable section of Amtrak’s network.