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.

Siemens has entered the North American locomotive market by storm, as Amtrak is utilizing an abundance of Siemens diesel-electric SC44 Chargers for use on various short-haul routes throughout the country. Furthermore, Amtrak has ordered an additional 75 Charger locomotives for use on long distance routes, with the option to order 100 additional units if necessary. These locomotives would supplement and eventually replace the GE Genesis locomotives, which have been the mainstay of the Amtrak diesel fleet for over two decades.

In addition to the Amtrak orders, Maryland commuter railroad MARC, ordered eight examples of the Charger locomotives. Furthermore, VIA Rail Canada has placed an order for 32 trainsets, including the SCB-40 variations of the Chargers, also Florida’s Miami-West Palm Beach Brightline utilizes 10 SCB-40 trainsets.

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.

Rob Pisani

Because the mainstay AEM-7 locomotives were beginning to show their age after many years of faithful service on the Northeast and Keystone Corridors, Amtrak began to offer bids to construct a new high speed electric locomotive for use on the busiest rail lines in the country. In 2010, Amtrak placed an order with Siemens mobility for seventy locomotives, at a cost of $466 million, which were slated to be delivered in early 2013. Upon delivery, a few examples were put to the test at the Transportation Technology Center (TTCI) in Pueblo, Colorado, while some went to the Northeast Corridor to begin learning their new stomping grounds.

Upon their implementation into service, Amtrak personnel, politicians, and enthusiasts alike flocked towards the tracks to catch a glimpse at the new motive power. Many realized their importance in the congested Northeast Corridor between Boston-Washington D.C., which proved to be the busiest passenger rail line in the country. With the implementation of the new locomotives, Amtrak hoped to reduce mechanical failures considerably, and implement more frequent services.


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.

Rob Pisani

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.

These locomotives operate on trains such as the intercity Northeast Regional and Keystone, while it also operates on long haul routes such as the Silver Service trains Crescent, Carolinan, and Cardinal. However, the ACS-64 only hauls the long distance trains as far as Washington D.C., where the electrified Northeast Corridor ends, and the trains run on either CSX or Norfolk Southern territory.

Rob Pisani

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 DateAmtrak: 2012-2015

SEPTA 2015-2018

Wheel ConfigurationB-B
TrucksSiemens SF4
Wheel Diameter1,117mm (43.98 in)
Curve Radius76 m (249 ft 4in)
Wheelbase9.9m (32ft 5.8 in
Length20.32 m (66 ft 8 in)
Width2,984 mm (9 ft 9.5 in)
Height3,810 mm (12 ft 6 in)
Axle Load54,250 lb
Adhesive Weight100%
Locomotive Weight215,537 lbs
Electric Systems12 kV, 25 Hz AC Catenary

12.5 kV, 60 Hz AC, Catenary

25 KV, Hz AC, Catenary

Electrical PickupPantograph
Traction Motors3- phase, AC, Fully Raised.
Head End Power1,300 hp 3 phase, 60 Hz, 480 VAC 100 kVA.
TransmissionPinion Hollow Shaft Drive
Multiple Unit CapabilityYes
BrakingRegenerative Braking. New York Air Brake

Electro-pneumatic cheek mounted disc brakes

Train BrakeElectro-Pneumatic
Max Speed125 mph
Horsepower8,600 hp
Tractive EffortStarting: 72,000 lbf

Continuous: 63,000 lbf

Factor of Adhesion33.4%
Brakeforce34,000 lbf



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