The locomotives with the numbers 56301 to 56388 were the first locomotives that the Turkish State Railways ordered in the USA. Since they still owned a few USATC Class S 160 and S 200 locomotives after World War II and the European factories were busy at the time, these locomotives were built for heavy freight service at the Vulcan Iron Works in Wilkes-Barre, Pennsylvania.

According to their origin, the fireboxes were the largest of all Turkish locomotives and were mechanically fed with a stoker. The boilers were also the largest and most powerful in Turkey. In accordance with US practice, the frames and cylinders were cast in one piece. In a total of five series, 88 pieces were delivered, which were known as “Skyliner” in Turkey. Until the mid-1980s they were mainly used in northern Turkey to pull heavy coal and ore trains and were then used as shunting locomotives for a number of years. Three are still preserved today, one of which is operational.