One year after the rollout, Union Pacific is ready to deploy a hybrid battery-electric switching locomotive in a working rail environment.
The Class I railroad (NYSE: UNP) and project partner ZTR Control Systems recently wrapped up testing of the first unit of a planned roster of six hybrid locomotives at UP’s Jenks Locomotive Shop in North Little Rock, Arkansas. The next assignment for the engine, numbered Y409, will be further testing in a yet-to-be-identified rail yard.
The first-of-their-kind hybrids for the North American rail freight business were rolled out in April 2024. Like hybrid autos, the locomotives can be powered by a standard diesel engine prime mover or stored battery power, with the battery recharging during engine operation. UP said in a video release that, depending on mode of operation, the hybrid switchers are expected to consume up to 80% less fuel than conventional diesels.
Railroads are testing a variety of alternative-fuel locomotives, powered by batteries, liquefied natural gas and hydrogen. But development has been gradual, as they have yet to replace the cheap and abundant power of diesel fuel. There are also no federal standards for alternative fuel power and little off-the-shelf technology designed for railroad applications.
The hybrid power runs in a mother-slug pair, with the prime mover in the mother unit and the slug providing extra horsepower and braking controlled by the mother.
The propulsion system was designed by ZTR of Minneapolis, while Union Pacific built the prototype at North Little Rock.
Testing on the next locomotive in the group is expected to begin in 2026.
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Find more articles by Stuart Chirls here.
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