Siemens ACS-64


Introduced in 2014, the Siemens ACS-64 is the mainstay of Amtrak’s high speed electric locomotive fleet on the Northeast Corridor. These locomotives replaced Amtrak’s aging AEM-7 locomotives, which have been in service since the early eighties. The ACS-64 is used on the Northeast Regional and Keystone service trains, as well as their long distance services, until switching to diesel power in Washington, D.C. The ACS-64 was first ordered in December of 2010, and delivered beginning February 2013. The ACS-64 was chosen due to its versatility and reliability needed on the highly congested Northeast Corridor, that shuffles commuters between Boston and Washington, D.C.

Although Siemens built many light rail vehicles for the United States, this was the first major American locomotive manufactured by Siemens. These units entered Siemens into the American locomotive market, and was quite a successful venture. These units are state of the art, as they included multiple safety systems, including crumple zones in the event of an impact, and knuckle couplers that could keep the passenger cars from turning over in the event of a collision.

Ryan Stavely photo


The ACS-64 (Amtrak Cities Sprinter 6,400 kilowatts), was designed to be a high horsepower, high efficiency locomotive, that allows the locomotive to accelerate up to eight Amfleet cars in 2 1/2 minutes. This high speed acceleration is ideal for the high volume environment of the Northeast Corridor. Stopping power on these locomotives include the addition of disk brakes as well as regenerative braking, in lieu of dynamic braking, which allows the locomotives to create energy formed from the brakes, and either use the energy immediately, or store it for later use.

To improve the reliability and efficiency of the new locomotive, the traction motors are fitted with two inverters per truck, in the event that one may fail, the other will continue to operate, and allow the locomotive to be kept in service. This is designed to prevent delays on the busy Northeast Corridor, and improve the reliability and operation of their services, and to provide increased customer comforts.

Before these locomotives were placed into service, they were rigorously tested at the Transportation Technology Center Inc (TTCI). These tests included acceleration with Amfleet cars, braking, and levels of energy efficiency.


These locomotives were placed into service in February of 2014, and continued to be delivered until August 2016. This officially phased out the AEM-7 locomotives, and the ACS-64 became the primary Amtrak locomotive on the Northeast Corridor.  Throughout their service life so far, they have proven to be reliable motors that are efficient and well engineered. These locomotives were purchased from Siemens for $466 million, with an option for three additional units. Amtrak ordered additional units to ensure that a service interrupting shortage did not occur.

Pjedro22 photo

European Counterparts

The ACS-64 is designed from the framework of the successful Euro sprinter, which is in passenger and freight use throughout continental Europe. The ACS-64 has been modified from the Euro sprinter to adhere to the American market, which included reinforcing the cab, and other safety devices that are required. These additions made the locomotive much heavier, however, increased the tractive effort of the locomotive.


Currently, Amtrak and SEPTA operate these units on the Northeastern portion of the country. SEPTA ordered their units in 2015, replacing their aging AEM-7 and ALP-44 fleet of locomotives. SEPTA ordered fifteen examples of the locomotive, with delivery beginning in December 2017, and introduced into revenue passenger service in July 2018, hauling Comet coaches on various SEPTA regional rail lines. SEPTA plans to utilize the ACS-64 with their future multilevel coaches currently on order from Bombardier.


Build Date Amtrak: 2012-2015

SEPTA 2015-2018

Wheel Configuration B-B
Trucks Siemens SF4
Wheel Diameter 1,117mm (43.98 in)
Curve Radius 76 m (249 ft 4in)
Wheelbase 9.9m (32ft 5.8 in
Length 20.32 m (66 ft 8 in)
Width 2,984 mm (9 ft 9.5 in)
Height 3,810 mm (12 ft 6 in)
Axle Load 54,250 lb
Adhesive Weight 100%
Locomotive Weight 215,537 lbs
Electric Systems 12 kV, 25 Hz AC Catenary

12.5 kV, 60 Hz AC, Catenary

25 KV, Hz AC, Catenary

Electrical Pickup Pantograph
Traction Motors 3- phase, AC, Fully Raised.
Head End Power 1,300 hp 3 phase, 60 Hz, 480 VAC 100 kVA.
Transmission Pinion Hollow Shaft Drive
Multiple Unit Capability Yes
Braking Regenerative Braking. New York Air Brake

Electro-pneumatic cheek mounted disc brakes

Train Brake Electro-Pneumatic
Max Speed 125 mph
Horsepower 8,600 hp
Tractive Effort Starting: 72,000 lbf

Continuous: 63,000 lbf

Factor of Adhesion 33.4%
Brakeforce 34,000 lbf


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