Nord 4-4-4 Locomotives in France

Class 2.251/222TA (Locobase 2135)

Data from Maurice Demoulin, Locomotive Actuelle ... (Paris: Librairie Polytechnique Ch.Beranger, 1906), pp. 135-138. See also Dr. R. Sanzin, "Die Lokomotiven auf der Intertionalen Austellung in Mailand 1906, 20. 2/6 gekuppelte Zwilling-Vorertzug-Tenderlokomotive der franzosischen Nordbahn ...", Zeitschrift des Oesterreichischen Ingenieur- und Architeckten-Vereines, Vol LVIII Nr. 51 (21 December 1906), pp. 718-719.

Known as "Revolvers" because they operated equally easily in each direction on the Grand Banlieue line. The stocky boiler included a Belpaire firebox, tall tanks, steam dome over the gap between the lead truck and the first driven axle.

Class Series 2.741 (Locobase 16044)

Data from "4-4-4 Compound Locomotive, Northern Railway (France)", The Locomotive, Volume 16 (14 May 1910), p. 100; "Locomotive with Marine-Type Water-Tube Firebos: Northern Railway of France", Railway Engineer, Volume 31, No 8 (August 1910), pp. 245-249. (Thanks to Alexander Blessing for his 1/1/2023 for his detailed description of some differences between the two variants; his cite of the Railway Express account led to a complete revision of the entry.)

The Nord's Gaston du Bousquet accepted steel maker Creusot's suggestion that he build a prototype boiler based on the widely used du Temple marine boiler. The basic layout involved mating a water-tube sided steam generator (i.e. firebox) to a conventional locomtive multi-tubular boIler. His first version proved unsatisfactory on several account, but one of the most glaring was the failure of the walls and bridge that used "refractory materials" (fire brick) in the front end of the firebox "where they were always rapidly destroyed."

In the second version, the design discarded the "masonry" in favor of a combustion chamber. As the LM report notes and the specification shows, the firebox in this locomotive was "quite exceptional". Its external dimensions were startling enough, but it was the profusion of heating surfaces composed of water tubes that extended into a combustion chamber that added up to the immense direct heating surface area.

The firebox's count of water tubes varied with their diameters. 290 tubes had inside diameters of 30 mm (1.2"), outside 35 mm (1.38"). Another 168 thicker-walled tubes had the same external diameter, but the inside diameter shrank to 25 mm (0.98"). An additional 44 tubes of the 30/35 mm diameter formed the sides of the combustion chamber

A more common feature was the use of internally finned Serve tubes. RE's extensive account includes diagrams that show the

The engine had started out as a 4-4-2 in 1907, but duBousquet wanted a larger grate that led to placing a bogie under the firebox. It wasn't too long, however, before La Chapelle rebuilt this locomotive as a conventionally arranged Ten-wheeler with a Belpaire firebox and superheated boiler.