In 2005, NRE used an older diesel locomotive for the first time to rebuild it as a multi-engine genset locomotive. The base was a Southern Pacific EMD MP15DC, originally built as a GP30. Instead of the 1,500 hp EMD 12-645E, two Cummins QSK19C, each with 700 hp, were used, both of which had their own generators. The driver's cab was here in the middle between the engines.

The type was called 2GS14B, which consists of two engines, “Gen Set”, 1,400 hp and wheel arrangement B-B. Other examples of this type have since been built on the basis of different four-axle road switchers, some of which had already been rebuilt. In most cases the cab stayed at one end of the locomotive. Other types with one to three engines soon emerged. Since then, other manufacturers, not only in the USA, have also been offering genset locomotives.