Kato N ES44AC Diesel BNSF 'Swoosh' #5801/DCC

The ES (Evolution Series) of locomotives are built by GE Transportation Systems and designed to meet the U.S. EPA’s Tier 2 locomotive emissions standards that took effect in 2005. These Evolution Series locomotives are equipped with AC traction motors and are powered by a newly designed “GEVO-12” 12 cylinder engine that produces the same power as the 16 cylinder AC4400CW, but with fewer emissions and greater fuel economy. It also carries a redesigned air-to-air dual-fan heat exchanger, which gives it its distinct “oversized” radiator; a common spotting feature for these new locomotives.

ES44DC: 

While the AC version has proven to be the overall most popular iteration of the “GEVO”, quite a few railroads elected to use the DC versions of these engines, including the BNSF Railway, Canadian National, and CSX.

ES44C4: 

The C4 is a variant of the ES44AC, using an A1A-A1A wheel arrangement with an idler axle in the center of each truck vs. the all-wheel power of its ES44AC brethren. This gives the engines the stability benefits of a six axle truck while reducing the number of traction motors from 6 to 4.