Order by CP during the first world war, the first 15 engines were built by Société Suisse pour le Constrution de Locomotives et Machines, in Switzerland in 1916, making the only Swiss built steam engines in Portugal. The other 12 engines were built in Germany as war reparations, having entered service in 1929. Design by Norwegian engineer, Olaf Kjelsberg, these engines counted on a power of around 1000 hp and 80 km/h of top speed. Being able to haul up to 700 tons, they were perfect for suburban traffic at Lisbon. With the line’s electrification of lines up to 1956, the locomotives were displaced to the north, at Contumil, and Barreiro at the south side of Lisbon. They also hauled the emblematic Sud Expresso and regional trains from Coimbra and Figueira Da Foz. In December 1944, engine 070 was started to be built at Lisbon General Workshops. It took 7 months, 450 workers and about 890 000 escudos (the currency of the time), which was 25% more expensive than the last ones of the series. A spare boiler was used and on February 6h, 1945, she was fired and run. This engine would later be repaired and persevered in Cascais until eventually was taken to the National Museum. As of other engines, they were initially built as coal burners but following WWII they were converted to oil.