Nord Beyer-Garratt Locomotives in France

Class 6.121 (Locobase 3251)

Data from "Locomotives at Liege," The Railway Magazine, Vol XI (15 August 1905), p.143. See also Dr. R. Sanzin, "Die Lokomotiven auf der Intertionalen Austellung in Mailand 1906, 34. 2x3/4 gekuppelte vierzylindrige Verbund-Tenderlokomotive der frazosischen Nordbahn ...", Zeitschrift des Oesterreichischen Ingenieur- und Architeckten-Vereines, Vol LIX, Nr. 12 (22 March 1907), pp. 211.-214; and "Sixteen-Wheel Double Tank Locomotive for the Northern Railway of France", Railroad Gazette, Volume XXXIX [39], No 14 (6 October 1905), pp. 322-324. Douglas Self''s entertaining "Unusual Locomotives" website supplied key details at [], last accessed 6 January 2019.

The RG account said the importance of the coal traffic and the profiles of the two main routes dictated the design. Over one of the options "the curves are of long radius and grades light". But the second one, which ran through Valenciennes, required helpers beyond that city to tackle grades of 1.2% while pulling 950 tons. On the flat, the designers were hoping for 30-37 mph (48-60 kph), while the locomotive might climb at 11-13 mph (18-21 kph).

In an attempt to lessen the energy loss entailed in leading steam exhausted from the HP cylinders powering the leading set all the way along a set of drivers to the LP cylinders at the rear, this du Bousquet design put the two pairs of cylinders under the center of the boiler. That is, two sets of Mogul wheel layouts faced each other under the steam dome. RG's page 323 offers diagrams showing the massive riveted backbone that provided rigidity to the locomotive.

Although it meant having a driver set lead the locomotive into the curves, the design certainly spread out the weight of the long side water tanks. At the speeds these engines were worked, the lack of leading truck probably didn't matter much. Also, the rear truck's mobility was limited to rotating around a central pivot only (which reduced steam leakage). The front truck had more degrees of freedom as well as carrying the water tanks.

The design obviously met with success and the growing stud initially operated from depots at Le Bourget and Hirson, where they worked the heavy coal trains on the Hirson-Valenciennes and Le Bourget-Lens routes. "However," Self added, "in the end most of their work was done on the Ceinture (Belt or Girdle) lines around Paris."

That service began in 1921 when 34 of the engines were assigned to the depot at Bobigny. The Ceinture services required tank locomotives able to travel in both directions with equal ease, and having enough tractive effort to draw heavy goods trains on an often difficult route profile, and the Du Bousquets met these needs effectively."

In 1935, the engines were reassigned to the main network as demand on the Ceinture had dropped.

Reder (1974) adds that similar engines went to China for the Peking-Hankow Railway, and to Spain for the Andalusian.