A Battery-Powered Alternative: Part One of a Two-Part Series

In the quest to conserve fuel and reduce emissions, Norfolk Southern has pioneered industry efforts to develop battery-powered locomotives.

Currently, the company is working on the second generation of our NS 999 electric prototype four-axle switcher locomotive. The NS 999, built on a reused 1969 Electro-Motive Diesel GP 38 platform, is designed to switch railcars in yard operations and is the first all-battery locomotive of its type. In addition to the NS 999, the company continues to research development of a hybrid electric six-axle long-haul locomotive.

Since work on the NS 999 began in 2007, Norfolk Southern has received three U.S. patents related to locomotive battery technologies. The latest, issued in February 2014, covers designs for a hybrid electric line-of-road locomotive equipped with a regenerative braking system to capture and reuse energy generated during dynamic braking. In one configuration, a battery-tender could be positioned between two diesel-electric locomotives to store the captured energy, using braking energy to recharge batteries and to power traction motors. A locomotive’s traction motors, which generate pulling power, are used in dynamic braking on hilly terrain to maintain safe speeds. On conventional locomotives, the braking energy generated – up to 3 megawatts of power – is blown off as heat through a resistor grid. Our eco-friendly hybrid approach to capture and reuse this energy to power traction motors would conserve diesel fuel and reduce emissions.

Since publicly introducing the NS 999 in 2009, the company has continued testing and refining the prototype to resolve technical operating challenges. The next-generation NS 999 will feature advanced lead-carbon hybrid batteries that replace conventional lead-acid batteries; a new modular container system to house the batteries; and a more technologically advanced battery management system.

Our development team has conducted around 300 simulated switcher cycles on a new battery-power system at the company’s testing lab in Roanoke, Va. In a partnership with Norfolk Southern, scientists at Penn State University’s Transportation Institute have done separate testing.

“Our testing shows that the systems are working as designed and that the batteries should have a long life in the locomotive,” said Gibson Barbee, our senior energy engineer.

Mechanical Department employees at the Juniata Locomotive Shop, who assembled the original NS 999, are outfitting the updated locomotive. If all goes as planned, the new and improved 999 will be ready for field testing in the summer of 2014.