Amtrak Airo
Passenger train
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The Airo program was initiated in 2019, with Siemens selected as the manufacturer in 2021. Amtrak initially ordered 73 trainsets in 2022, later increasing the order to 83 in 2023. Funding for those 83 trainsets was provided under the Infrastructure Investment and Jobs Act of 2021. Another 43 trainsets were ordered for state-supported services in August 2026, using up to $2.05 billion in funding from the Federal Railroad Administration's National Railroad Partnership Program, though the exact number of trainsets by type is unknown.
In March 2025, 83 coach cars and 9 locomotives had been completed, with 23 coaches in final assembly stages. In July 2025, the first trainset was completed and sent from the Siemens plant in Florin, California to the Transportation Technology Center (TTC) near Pueblo, Colorado for testing. In October 2025, the trainset passed testing at the TTC and was sent for additional testing on the Northeast Corridor. On February 10, 2026, the first Airo trainset was unveiled at a preview event at Washington Union Station.In May 2026, the first Airo trainset, destined for the Amtrak Cascades service, began additional testing, staff training, and practice runs in the Pacific Northwest. On May 28, 2026, the first catenary-diesel, dual-mode trainset for the Northeast Regional was completed.
Service started on the Amtrak Cascades on September 30, 2026 with two trainsets operating four daily trips. Service on the Northeast Regional is expected in late 2027, and on the Carolinian, Downeaster, Keystone, Palmetto, Pennsylvanian, and Vermonter in 2029. Service is expected to start in 2030 on the Adirondack, Empire Service, Ethan Allen Express, and Maple Leaf.
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Operations
Most Amtrak Airo trainsets are designed to operate on both electrified and non-electrified lines without the need to change locomotives. This is achieved through a hybrid configuration using a Siemens Charger ALC-42E diesel-electric locomotive and either an Auxiliary Power Vehicle (APV) or a battery car.
The Airo trainsets will replace the Amfleet I and Horizon coaches, as well as the Talgo trainsets on the Amtrak Cascades service. Amtrak claims safety and reliability improvements by managing operations across entire trainsets rather than on individual cars. Safety will be improved from reducing yard switching, journey times will be shortened by eliminating time-consuming locomotive changes, and reliability will be improved from synchronizing maintenance across a whole trainset rather than on individual cars.
The trainsets have conventional Janney couplers on the front of the locomotive and control car, but the connections between the passenger cars are fixed drawbars, therefore, permanently coupled trainsets. Because of this, equipment wear from constantly coupling and decoupling individual cars will also be reduced, which is necessary with the current fleet as individual cars on a train may be on different maintenance schedules and often need to be removed and replaced. Extensive renovations to maintenance facilities will be done so that they can handle the trainsets.
Types
There are three types of Airo trainsets, known within Amtrak as the "B", "C", and "D" sets, with different propulsion types. Additionally, there are 3 subtypes of the “B" trainsets.
The dual-mode B trainsets are designed to operate on both electrified and non-electrified lines without the need to change locomotives. This is achieved through a hybrid configuration that includes a diesel-electric locomotive (Siemens Charger ALC-42E), and an Auxiliary Power Vehicle (APV). The APV is only used on track with overhead lines. It is the car closest to the locomotive, and is equipped with two pantographs, an underfloor main transformer, and two powered trucks. The remainder of the car has business class seating. In electrified territory, the APV draws power from overhead lines into the four traction motors in the APV, and, via a DC link cable, into the four traction motors in the ALC-42E locomotive. In diesel mode, the motors in the APV are not used. Having the heavy transformer in the APV instead of the locomotive better spreads out the weight and reduces track wear.
There are three subclasses of the B trainsets. B1A sets are 6 cars long and will be used on the Downeaster and Keystone services. The B1B sets are also 6 cars long, but has additional baggage space in the cab car and fewer seats, and will be used on services such as the Carolinian, Palmetto, and Pennsylvanian, which offer checked baggage service. The B2 sets are 8 cars long and will be used on Northeast Regional services.
The dual-mode C trainsets are 6 cars long as well, but they will have batteries installed instead of the APV's electrical equipment. These sets will be used on the Adirondack, Empire Service, Ethan Allen Express, and Maple Leaf, Amtrak's routes that access New York Penn Station via the Empire Connection tunnel. Although the tunnel has third rail electrification, the trainsets will operate using the onboard batteries. In diesel mode, the batteries will not be used. The initial sets, to be delivered in 2028, will be part of a pilot to determine the viability of using battery technology in the tunnel. If the battery pilot proves unviable, later trainsets may use third rail instead of a battery.
The diesel-only D trainsets operate without an APV or batteries. The trainsets also have additional baggage space in the cab car. These 6 car sets operate only on the Amtrak Cascades service. Three of the total order of 8 D trainsets are paired with new ALC-42E locomotives. The remaining 5 trainsets were delivered without locomotives and are paired with existing SC-44 locomotives.