Known also as an Ultra Low Emissions Locomotive (ULEL), the GenSet engine was the brainchild of Mike Iden of the Union Pacific. Looking to reduce fuel consumption and emissions, Iden envisioned a diesel locomotive with multiple engine/generator sets, each of which would turn on only when needed. Working with diesel builder and remanufacturer National Railway Equipment, Iden created an experimental prototype that proved its worth in 2005 and spawned a new type of road switcher - the ultimate "smart" locomotive.
Today's NRE 3GS-21B - 3 Genset, 2100 horsepower, B-truck (4 wheels) - is perhaps the perfect marriage of heavy machinery and computers. Each of its three 700-horsepower GenSets turns on only when a microprocessor senses it's needed. At idle (which is a majority of the time for a switcher), only one engine runs, and even that turns off after a certain period of inactivity. Unlike traditional railroad diesels that require an elaborate startup procedure, the Cummins diesels used in GenSets are based on a truck engine design that can be started up instantly. When the locomotive is under load, the second and third GenSets power up and down as needed. The result is a locomotive that delivers fuel savings of 40% and more, compared with traditional yard and road switchers, and an 80% reduction in noxious emissions. No wonder that many GenSet purchases have been funded with government grants targeted at making the air more breathable.
Software also enables a GenSet engine to work longer and harder. Its computer tracks the running time on each engine-generator set and evens out the wear on the locomotive's three units - each of which is skid-mounted and can be changed out in less than six hours if necessary. The 3GS-21B has unusually high tractive effort for its horsepower because a microprocessor controls wheel slip by reducing power to individual traction motors - rather than a whole truck as on older wheel-slip prevention systems. This feature has enabled some customers to do the same work with fewer locomotives. And, like the M.T.H. DCS system, the 3GS-21B has software that can be upgraded over the Internet.
In 2017, these Proto-Sound 3.0 equipped NRE "Engines of Change" feature the superb level of detail you expect in a Premier model, as well as Cummins diesel recordings from an actual 3GS-21B and, like the prototype, the sound of additional GenSets coming on line as you advance the throttle. If you're running the latest low-emissions EMD and GE diesels on your main line, you'll surely want a GenSet or two for your branch line or yard.