The NRE 3GS21B is a low-emissions diesel genset locomotive built by National Railway Equipment (NRE). It is powered by three Cummins QSK19C I6 engines with each one developing 700 horsepower (522 kW) and creating a total power output of 2,100 horsepower (1,570 kW). Instead of a single prime mover, the NRE genset locomotive has three engines that each can be turned off or on as power is needed 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.

NRE 3GS21B
A new NRE 3GS21B locomotive in the Union Pacific scheme.
Type and origin Power type Diesel-electric Builder National Railway Equipment (NRE) Model 3GS21B Build date December 2006 (2006-12) – Present Total produced 182
Specifications Gauge 4 ft 8+1⁄2 in (1,435 mm) Prime mover Cummins QSK19C (×3) Engine type Diesel engine (×3) Aspiration Turbocharger (×3) Cylinders 6 (×3)
Performance figures Power output 2,100 hp (1,570 kW)
Career Operators See list

Flexibility

Because the engines are modular, flexibility is obtained:

• If one engine fails, the others can continue at reduced power.
• If a lower axle load is needed, one engine can be left off.
• When reduced power is needed, one or more of the engines can be turned off, saving fuel and wear and tear.
• The QSK19C engine is common to the four variants of the NRE 3GS21C locomotive.
• The QSK19C engine is also widely used for non-railway applications, and spare parts are readily available.[3]

Original buyers

• 
  A brand new 3GS21B locomotive painted for the BNSF Railway.
• 
  An NRE 3GS21B leads a Union Pacific train along street running trackage at Anaheim, California.
• 
  Two brand new U.S. Army 3GS21B locomotives working at Fort Lewis, Washington.
• 
  Brand new MBTA 3GS21B at South Station.
• 
  MBTA 3GS21B on the Grand Junction Railroad.

See also

• NRE 3GS21C

References

External links

External images
RailPictures.Net – NRE 3GS21B photographs from RailPictures.Net.
Railroad Picture Archives – Photographs of the NRE 3GS21B at Railroad Picture Archives.

Wikimedia Commons has media related to NRE 3GS21B locomotives.

• National Railway Equipment – Official N-ViroMotive Product Page