Three years ago, Amtrak announced it had ordered 70 new locomotives that would serve the Northeast Corridor. Now, they're finally starting to arrive.

Earlier this spring, two of the locomotives arrived at a Department of Transportation facility in Colorado, and this month, a third arrived at Amtrak's operations headquarters in Delaware. They'll undergo months of testing and should be up running along the East Coast this fall.

The locomotives, which Amtrak purchased from Siemens, will replace all 62 of the existing electric locomotives that currently serve the Northeast Corridor. The higher-speed Acela trains will remain.

Officials with the rail provider say the new locomotives -- known as the Amtrak Cities Sprinter -- will be more reliable than their predecessors. The existing fleet of electric locomotives on the NEC average more than 3.5 million miles, and many of them are more than 25 years old.

Want more transportation news? Click here.

The $466 million purchase was financed by a federal loan and will be repaid by receipts from ticket sales. The full federal loan is worth $563 million, which includes spare parts, facilities management, and other costs affiliated with the new locomotives.

The trains will operate at up to 125 miles-per-hour on the NEC and 110 miles per hour on the Keystone Corridor, which runs between Philadelphia and Harrisburg, Pa.

Once testing is complete on the first three locomotives, Siemens will ratchet up production on the remaining 67 vehicles, with a few delivered to Amtrak each month through 2016.

The purchase hasn't been without criticism. The New York Observer has said that Amtrak wound up with trains that are heavier and slower than their European counterparts, largely as the result of Federal Railroad Administration regulations.

And a recent report from Amtrak's Inspector General accused the government-subsidized company of making the commitment to purchase 70 locomotives without adequately analyzing how many it really needs.

The IG also questioned why Amtrak plans to replace 15 locomotives that had been in service for 11 to 13 years, only about halfway through their expected service life.

The report estimates that Amtrak needs only 56 new locomotives -- not 70 -- to meet peak demand on a typical day and says the company hasn't analyzed whether improved maintenance might ensure more trains can be in service without a purchase that's quite so large. The difference in cost between 56 and 70 locomotives is about $167 million including finance costs.

Amtrak officials, according to the IG, also believe purchasing the 70 locomotives was necessary because the company isn't assured of the level of funding it will have in the future.

Amtrak officials haven't argued with the thrust of the IG's report and say they are revamping the way they analyze equipment needs. They're also working to update Amtrak's fleet plan to better align it with a broader strategic plan, a spokesman said. Those changes "will provide improved analysis for decision-making and support our goal of running Amtrak more like a business."

The locomotives could make many aspects of Amtrak's operations more efficient, several officials told Governing. The Cities Sprinter will replace three different types of locomotives. That means it will be easier to train mechanics and engineers, since they'll have to learn fewer types of equipment. And there should be savings achieved by placing larger orders for uniform replacement parts.

They've also portrayed the purchase as an economic driver. The locomotives were assembled in Sacramento and built with parts from plants in Ohio, Georgia and Mississippi. Federal standards required more than half of the components to come from American suppliers.

Amtrak officials have touted safety features of the new locomotives, highlighting the fact that not only do they meet federal safety regulations but include other safety features that aren't yet required, such as technology to keep the train upright and on the tracks even in the event of a collision.

Officials say the design also will make maintenance easier, allowing for faster turn-around-times when a locomotive has to undergo repairs. The new locomotives are also more energy efficient than their predecessors and have regenerative technology that that recovers energy used during braking.