The NRE 2GS12B is a low-emissions diesel genset switcher locomotive built by National Railway Equipment Company as part of its N-ViroMotive series of low-emission locomotives. It is powered by two Cummins QSK15 I6 engines with each one developing 600 horsepower (447 kW) and creating a total power output of 1,200 horsepower (895 kW). The locomotives are compliant with the EPA's Tier 4 emissions standards requirements for non-road diesel engines.