Amtrak Airo is a new class of intercity, high-speed passenger trainsets being built by Siemens Mobility for Amtrak. The trainsets are based on the Siemens Charger ALC-42E locomotives and Siemens Venture passenger cars, and are intended to replace older equipment used on the Northeast Corridor and state-supported routes throughout the United States.
Service is expected to start on the Cascades in late 2026. Service on the Northeast Regional is expected in 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.
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 APV will be used on trains that use track with overhead lines (catenary).
Diesel electric locomotives are somewhere on the order of 100 times the efficiency of tractor trailers, which are themselves much more efficient than cars per ton-mile. If all road transit was replaced by diesel electric trains it would cut transit emissions to almost nothing. That of course would still only eliminate a fraction of total emissions, since most emissions are not transit-based.