Norfolk Southern Railway Company (NS) is developing an all-electric switching locomotive, the NS 999, to provide a zero point source emission electric locomotive option for rail switching service. The original NS 999, unveiled in September 2009, suffered from poor battery management and challenging battery packaging. The rebuilt NS 999, anticipated in the 4 th quarter 2013, will be powered by Axion Power’s PbC ® batteries. The Axion PbC ® batteries provide increased charge/discharge cycle life and charge acceptance compared to conventional Valve Regulated Lead–Acid (VRLA) batteries, as well as increased usable energy when configured in series as ‘long strings.’ NS and Axion will review the challenges of the initial NS 999 battery management system, improvements to the battery management system, and test results from the Norfolk Southern Hybrid Locomotive Simulator using Axion’s PbC ® lead–carbon hybrid battery/supercapacitor. Axion will present test data showing the low variation in strings of PbC ® batteries compared to VRLA while simulating locomotive switching. PbC ® batteries have a unique charging curve, known as “concave down, increasing,” which allows the batteries to self-equalize in strings. This characteristic of PbC ® batteries provides for simpler battery management and reduced maintenance charging, while increasing the usable energy available within the string. The rebuilt experimental locomotive NS 999 will use Axion’s PbC ® lead–carbon batteries for the energy storage system to power locomotive switching and recover braking energy. If this research is successful, a zero point source emission electric locomotive could provide an option to reduce emissions in urban non-attainment areas and reduce dependence on petroleum. The NS 999 electric switcher is the first step to the ultimate goal of recovering braking energy from high power conventional diesel locomotives.