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Siemens ALC42 "Charger" Locomotives

Published: November 22, 2023

By: Adam Burns

The ALC42 is one of Siemens Mobility's diesel-electric passenger models and part of its "Charger" family of locomotives.   Other variants in this line include the SC-44, SCB-40, SC-42DM, and SCV-42 manufactured for other agencies.

The ALC42 was built specifically built for Amtrak's long-distance services and will eventually replace the carrier's fleet of General Electric "Genesis" series.

Like its GE counterpars, the model features a streamlined carbody. It is also equipped with a 4,200 horsepower engine, and meets the latest EPA Tier IV emissions standards. Finally, it includes safety features such as crash energy management components and other state-of-the-art components.

The locomotive is brand new to the Amtrak fleet; the first example began production in 2020 and was completed the following year.  The first unit to enter service did so in 2022 and there are currently 125 examples in production at Siemens.


02834263526835798125872386364374.jpgAmtrak ALC42 "Charger" #315 leads the westbound "Capitol Limited" during a station stop in Martinsburg, West Virginia on July 13, 2023. This was the first time one of the new units had led this train west out of Washington D.C. Jon Wright photo.


The ALC-42, popularly known as the 'Charger', is a diesel-electric locomotive manufactured by Siemens Mobility. The first unit in the series began production in March, 2020 and #300, to Amtrak on June 17, 2021.  

The impressive locomotive subsequently entered revenue service on February 8, 2022 leading the Empire Builder, thus marking a significant evolution in the locomotive industry.

Siemens Mobility, a subsidiary of the German conglomerate Siemens AG, has carried out production of these locomotives at its plant located in Florin, California (Sacramento).


The versatile ALC-42 was designed as a state-of-the-art replacement for Amtrak's older locomotive models, notably the P40DC, P42DC, and non-rebuilt P32-BWH units. These predecessors had served Amtrak since the early 1990s, necessitating a modern successor that could match the evolving advancements in railway technology.

The manufacture of these locomotives was scheduled after the production of the ACS-64. Siemens Mobility completed these 70 electrified units for Amtrak's Northeast and Keystone Corridors between 2013 and 2016, paving the way for the development of the ALC-42 line.

Amtrak, being the prime customer for the ALC-42, initially ordered 75 of these locomotives to modernize its long-distance and state-supported routes. The deal was established under a comprehensive multi-year plan between Siemens Mobility and Amtrak. However, in 2022 they placed an order for an additional 50 units, which will bring the fleet up to a total of 125.

The initial road numbers range from 300 to 374 while the new units are expected to be numbered 375-424.  Amtrak's total cost for the acquisition of the 75 units stood at an estimated $850 million. This significant investment echoed Amtrak's commitment to modernizing its fleet and enhancing passenger experiences.

The ALC-42 boasts of remarkable technical specifications. The locomotive stands as a symbol of immense power with a horsepower rating of a stout 4,200. It holds an initial tractive effort of 65,000 lbs, stretching 69 feet 4 inches in length, 16 feet 2 inches in height, and 10 feet 8 inches width.

The locomotive flaunts a wheelbase of 39 feet 2 inches and weighs a colossal 292,000 pounds. Its maximum operating speed is an impressive 125 miles per hour. The ALC-42 implements a 480-volt AC and 64-volt DC hotel power system.


Years Produced
Wheel Arrangement
71' 6"
14' 8 13/32"
Wheel Base
40' 9 19/32"
Wheel Diameter
280,000 Lbs
Cummins QSK95 (16 cylinder)
Maximum Speed
125 mph
Tractive Effort (Starting)
65,000 Lbs
Tractive Effort (Continous)
62,000 Lbs at 40 mph
Minimum Curve Radius
Head End Power (HEP)
1,000 HP
Fuel Capacity
2200 Gallons


In addition to the existing fleet, a planned variant, dubbed as the ALC-42E, is on the horizon. This variant functions on both electric and diesel power, offering operational flexibility similar to Electro-Motive's classic FL9.

The ALC-42's sleek, productive design is a representation of Siemens Mobility's commitment to advancements in railway technology. The locomotive prioritizes passenger comfort, sustainability, and increased operational efficiency.

It delivers not just in performance but also in aesthetics. Its modern exterior boasts a distinct, streamlined design, amplifying its presence on the tracks.


The use of the ALC-42 has significant implications for sustainability. It complies with the latest EPA Tier IV emissions standards, reflecting Amtrak's push towards environmentally-friendly operations.

The ALC-42's impressive specifications don't stop at its exterior. Its interior houses a technologically advanced control system that enhances usability and reduces driver fatigue.

Adaptability is another notable feature of the Charger. Its universal design allows flexibility in operation over both long-distance and regional passenger services.

Moreover, the Chargers are equipped with creature comforts such as onboard Wi-Fi, power outlets, and bicycle racks, providing passengers with a comfortable and connected journey.

Engineered to enhance passenger safety, the locomotives come with advanced crash energy management features, including crumple zones, to minimize the impact in the event of a collision.

ALC-42s have been crafted to meet the demands of a modern rail network. Their modern control systems, combined with top-of-the-line sound dampening features, offer a smoother, quieter ride - making journeys more comfortable for passengers.

These new Chargers don't just make strides forward in passenger experience; their advanced engine technology significantly reduces harmful emissions, contributing positively to environmental cleanliness.

Their performance-oriented design also aids in reducing operational and maintenance costs. Key design features, such as an easy engine and alternator change-out process, make maintaining these locomotives simpler and more cost-effective.

The Charger's introduction also marked a significant milestone for Siemens Mobility. The successful collaboration with Amtrak further solidifies its position as a global pioneer in design and manufacturing of locomotives.

It is interesting how the production of passenger locomotives has shifted over the years from builders like EMD and GE to now Siemens.

Simultaneously, the procurement of the fleet complements Amtrak's strategic goals of modernizing its locomotive fleet, reducing fuel usage, and maintenance costs, while also ensuring a considerable reduction in greenhouse gas emissions.

The advent of the series also provides job security for the local communities surrounding Siemens’ manufacturing and service facilities, providing them with notable economic benefits.

One crucial aspect of the locomoitve is its potential for further upgrades and possible development of new variants like the ALC-42E, indicating that Siemens and Amtrak are looking towards the future of rail transportation.

It's worth noting that the Charger’s engine is fuel-efficient, helping Amtrak to maintain operational costs while aiming for environmentally friendly functioning.

While the predecessor locomotives have been significant in their time, the introduction of the ALC-42 represents a considerable leap forward, setting new standards for railway operations in the United States.

The locomotive retains the best of its predecessors while representing progress in locomotive technology. The Charger stands as a testament to ensuring comfort, efficiency, and sustainability in railway transportation.

The Charger is not just a machine; it holds an essential position in the narrative of Amtrak's history. It represents the transformation the organization has undergone over the years, continuously adapting to technological advancement and environmental consciousness.

Through the introduction of Charger, Siemens Mobility continues to demonstrate its capability in building some of the world's most efficient and reliable diesel-electric locomotives.

The locomotive plays a vital role in improving Amtrak's performance and overall passenger service quality, promising smoother and faster journeys for its consumers.

The ALC-42 serves as a potent example of the potential of diesel-electric locomotives in modern rail travel. It stands as a symbol of forward-thinking technology and sustainable measures in the transportation sector.


In summary, the Charger is more than just a locomotive. It is the embodiment of innovation, technology, and sustainability in the railway industry. Its impact on Amtrak and the wider rail network cannot be overstated.

While the ALC-42 continues to write its story on the rails, it also continues to leave a significant mark on the global railroad landscape. It is, undoubtedly, a vital player in the industry shaping the future of rail technology and contributing to the development of sustainable practices.

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