When the Greek railway network was connected to the main European network, the Hellenic State Railway needed powerful locomotives for passenger service on lines with grades of two percent and curves of 300 meters. Now, the complete journey from Paris to Piraeus was to be completed in less than 60 hours. After the start of World War I, the ordering of locomotives from other European countries had become difficult.

So they were built by ALCO-Schenectady and assembled in Greece. With the wheel arrangement 2-8-2, they had drivers of 60 inches or 1,524 mm. Built to operate with high-grade coal from South Wales, whey had a grate of 34.7 square feet or 3.22 m² and were superheated. They could reach a speed of 80 km/h on level lines and on a two percent grade, they could haul 250 tonnes with 25 km/h.