Union Pacific 3GS21B Y2723 is a low-emissions diesel genset locomotive built by National Railway Equipment (NRE) at their Mount Vernon shops in Southern Illinois. Instead of a single prime mover, the NRE genset locomotive is powered by three separate 700 horsepower (522 kW) Cummins QSK19C engines, providing a total power output of 2,100 horsepower (1,570 kW). Each engine could be individually started or shut off depending on load reducing overall diesel emissions and improving fuel efficiency. (Anaheim, California – September 10, 2010)
