News & Reviews News Wire Union Pacific to partner on construction of hybrid-electric locomotives

Union Pacific to partner on construction of hybrid-electric locomotives

By Trains Staff | October 6, 2022

| Last updated on February 16, 2024


Railroad and technology firm ZTR will build six units at UP’s North Little Rock shops

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Union Pacific’s Bailey Yard
Cars roll down the eastbound hump at Union Pacific’s Bailey Yard in North Platte, Neb., in June 2018. UP will build hybrid-electric locomotives for yard service at its shops in North Little Rock, Ark. Bill Stephens

OMAHA — Union Pacific, which has already made the biggest commitment to battery-electric locomotives of any North American Class I railroad, is taking another big step into alternative forms of motive power.

The company announced today (Thursday, Oct. 6) that it will partner with green technology firm ZTR to build hybrid-electric locomotives at its North Little Rock, Ark., shops. The prototype unit is expected to be delivered in late 2023 with five more locomotives constructed in 2024.

The hybrids, like a plug-in hybrid automobile, will offer multiple modes of operation and be able to charge onboard batteries in several ways, including wayside and onboard charging. They are planned to operate in mother-slug sets, with a diesel locomotive connected to a slug unit equipped with batteries, electronics, and controls supplied by ZTR.

“Adding hybrid-electric locomotives to our fleet is another important step for Union Pacific as we work to explore ‘drop-in’ technologies that modify current systems and reduce our carbon footprint,” Shane Keller, Union Pacific senior vice president of engineering and mechanical, said in a press release. “This pilot will help make our fleet more fuel efficient and further advance our commitment to reaching our sustainability goals, while testing the technology’s capability for expanded use across our locomotive fleet.”

The new locomotives — to be converted from older, higher-emission units — will be used chiefly in yard operations, with the mother-slug configuration increasing the traction motors available for the pulling and braking power needed for such work. UP already uses more than 65 mother-slug sets with ZTR technology in yards across its system.

“ZTR is proud of our long-standing relationship with Union Pacific and excited to partner with them on this hybrid-electric locomotive development,” said ZTR Control Systems President Derek Shipley. “This investment aligns well with our ongoing goal to leverage ZTR’s technical expertise to support railways in their decarbonization and efficiency improvement efforts. This initial hybrid-electric mother-slug application will be the basis of our design for future hybrid-electric, long-haul and fully electric solutions.”

UP has previously ordered 20 battery-electric locomotives for yard service — 10 from Wabtec and 10 from Progress Rail [see “Union Pacific orders …,” Trains News Wire, Jan. 28, 2022]. Those locomotives will be tested in North Platte, Neb., and in the Los Angeles basin. UP did not immediately indicate where the newly announced units might be used.

8 thoughts on “Union Pacific to partner on construction of hybrid-electric locomotives

  1. Deja vu all over again.

    NYC used three-power locomotives in NY City, notably on the West Side Freight Line. Starting in 1928, power was a fleet of locomotives that could operate from third rail or batteries, and each unit had two 300 HP Ingersoll-Rand diesels to charge the batteries.

  2. According to the Omaha-Nebraska headquartered UP,
    moving freight by rail instead of truck reduces GHG emissions by up to 75%, adding that, on average, UP moves a ton of freight 463 miles on a single gallon of diesel fuel.

    Dr. Güntürk Üstün

  3. Union Pacific published its first comprehensive Climate Action Plan in December 2021, outlining its efforts to significantly reduce emissions within its operations. As part of that commitment, Union Pacific will reduce absolute Scope 1 and 2 GHG emissions 26% by 2030 and achieve net zero greenhouse gas emissions by 2050.

    Dr. Güntürk Üstün

  4. Great Union Pacific Railroad! Always on the move, always pioneering, always innovative, and always a proud element of the United States railway sector!

    Dr. Güntürk Üstün

    1. The funny part about molten salt reactors was that the initial design impetus came from the Aircraft Nuclear Propulsion program with a lower power version of the reactor proposed for nuclear locomotives.

      I prefer to keep fission products in oxide fuel pellets encased in zircalloy cladding.

  5. They need to partner with GM or Ford because this technology is needed in the truck market even more than locomotives. Battery technology on it’s own has far to many drawbacks that outweigh the benefits of the electric motors.

  6. In some ways it is back to the future. Steam locomotives hauled their fuel behind them. This is doing much the same, since the main guts of the locomotive is controls and traction motors.
    Unlike the old days, if you can standardize the interface and controls, you can haul any source of electricity behind you and it makes no difference. It might even make sense to mount a pantograph there in mixed systems and then drop it off and pick up a difference source when you are out of overhead wired heavy traffic territory.

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