Nord 3.628 is a member of the Class 3.513 4-6-0s (230s). It is a de Glehn – du Bousquet compound locomotive design. The class first entered service in 1908 with a total of 149 locomotives built. The first 25 machines were built with slide valves; with the remainder featuring piston valves as well as being superheated. (The earlier locomotives were converted later.) The locomotive design also features a Lemaître blastpipe. The class were intended as mixed traffic engines however they proved exceptionally free-running and were found capable of hauling express passenger trains.