| NRE 3GS21B | |
| Powertype: | Diesel-electric |
| Builder: | National Railway Equipment (NRE) |
| Builddate: | - Present |
| Buildmodel: | 3GS21B |
| Cylindercount: | 6 (×3) |
| Primemover: | Cummins QSK19C (×3) |
| Enginetype: | Diesel engine (×3) |
| Aspiration: | Turbocharger (×3) |
| Poweroutput: | 2100hp |
| Totalproduction: | 182 |
| Operator: | See list |
The NRE 3GS21B is a low-emissions diesel genset locomotive built by National Railway Equipment (NRE). Instead of a single prime mover, the NRE genset locomotive is powered by three separate 700hp Cummins QSK19C engines providing a total power output of 2100hp. Each engine could be individually started or shut off depending on load reducing overall diesel emissions and improving fuel efficiency.[1] More than 150 of the 3GS21B genset locomotives have been produced to date, with the majority of these units being manufactured at NRE's Mount Vernon shops in Southern Illinois.[2] In addition, three road slug models have also been produced.
Because the engines are modular, flexibility is obtained:
| Railroad | Quantity | Road numbers | Notes | |
|---|---|---|---|---|
| 1293-1294 equipped with dynamic brakes, classified as 3GS21B-DE | ||||
| Both units equipped with dynamic brakes, classified as 3GS21B-DE, 2100 retired 5/13, 2101 retired 6/13 (both returned to NRE). | ||||
| Both units equipped with dynamic brakes, classified as 3GS21B-DE | ||||
| Metro Stevedore[4] | Equipped with dynamic brakes, classified as 3GS21B-DE | |||
| Neptune Bulk Terminals[5] | 805A, 808A and 809A are the only road slug model built to date. | |||
| Total | 182[6] ! | |||