UP, ZTR Partner on Hybrid-Electric Locomotives (UPDATED, 6/27)

(UP photo)

The first of six cutting-edge hybrid battery-electric locomotives designed and built by Union Pacific (UP) and its partner ZTR, a locomotive control systems supplier, are currently being tested at a UP facility and rail yard.

“This is an incredibly exciting pilot project with great potential to improve the fuel efficiency of our locomotive fleet,” said UP President Beth Whited. “It underscores our strong commitment to exploring and developing alternative energy sources while reducing our carbon footprint and advancing our sustainability goals.”

UP and ZTR first announced on Oct. 6 a partnership to build the hybrid-electric locomotives. ZTR designed the hybrid propulsion technology, while UP built the prototype at its North Little Rock, Ark., facility. The next of the remaining five hybrid locomotives is expected to be ready for testing next year.

“We are excited about the groundbreaking hybrid technology built in partnership with Union Pacific. Union Pacific is serious about reaching their sustainability goals and they have been an outstanding partner in this project,” said ZTR CEO and President Sam Hassan. “The development of the ZTR BLU™ Technology platform is one of the most significant projects for ZTR to date and will be the basis for further advancements in sustainable solutions, including emission-free locomotives.”

Known as “mother-slug” sets, the hybrid locomotives will operate with one locomotive running on diesel and an accessory or “slug” unit providing battery power. In “keeping with its sustainability commitments,” UP converts older locomotives, typically with higher emissions, the Class I says. The slug unit will be converted and equipped with batteries, power electronics and controls supplied by ZTR, helping to “achieve fuel and maintenance savings and offer environmental benefits” allowing the hybrid-electric “mother-slug” to operate in single-engine, battery charging or electric only modes. UP says, much like today’s plug-in hybrid car, the locomotives can operate in multiple modes with several ways to charge the locomotive batteries, including wayside and onboard charging.

The new locomotives, UP says, will be used chiefly for yard operations with the engineless slug increasing traction motors available to the locomotive, “boosting the pulling and braking power that is key for this kind of work.”

UP began rolling out “mother-slug” sets with ZTR’s Nexsys control systems in 2017 and currently operates more than 65 in yards systemwide. Depending on the mode of operation, fuel savings and greenhouse gas emission (GHG) reductions could total up to 80%, the Class I says.

“Adding hybrid-electric locomotives to our fleet is another important step for UP as we work to explore ‘drop-in’ technologies that modify current systems and reduce our carbon footprint,” said UP Senior Vice President of Engineering and Mechanical Shane Keller. “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.”

“ZTR is proud of our long-standing relationship with UP 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.”

According to the railroad, 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.

UP 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, UP says it will reduce absolute Scope 1 and 2 GHG emissions 26% by 2030 and achieve net zero GHG emissions by 2050.

Earlier this year, UP announced a $1 billion agreement with Wabtec Corporation for 600 locomotive modernizations–the “largest investment in modernized locomotives in rail industry history,” as well as the purchase of 20 battery-electric locomotives apiece from Progress Rail, a Caterpillar Company, and Wabtec, representing “the largest investment in battery-electric technology by a U.S. Class I railroad.” Deliveries are expected to begin in late 2023 and run through late 2024.