2-4-0 Steam Locomotives in France

Class 2834 (Locobase 7409)

Data from Titre Exposition universelle internationale de 1889 a Paris. Rapports du jury internationale. Auteur - Volume France. Ministere du Commerce, de l'industrie. Picard, Alfred, ed. Volume Groupe VI - -Outillage et precedes des industries mecaniques. Electricite (5e partie) Classes 60 a 63. Rapport sur le materiel des chemins de fer; tables beginning on p. 183 ([] (accessed 1 September 2005).

The Jury's report says that this six-wheeled express engine was analogous to the 4-4-0s then in service with the same railroad. They were derived from the earlier dozen locomotives of the 2821 class described in Locobase 20220.

The Belpaire firebox added some area, but the design wasn't particularly outsized. The inside, HP cylinders were actuated by Stephenson valve gear and drove the front axle. The outside, LP cylinders drove the rear set of drivers and got their steam through Walschaert gear.

The LP/HP ratio was relatively low at a little less than 2:1. Later 4-4-0s by the same builder would show a more typical ratio.

Class 621/2.821 (Locobase 20220)

Data from "Forty Years of Locomotive Building for a Great French Road", Engineer, Volume 69 (20 June 1890), p. 492.

The author describes these as a significant enhancement over earlier classes. They were followed by 27 larger four-cylinder compounds shown in Locobase 7409.

Class mixte (Locobase 11342)

Data from L Chatelier, E Flachat, J Petiet, and C Polonceau, Guide du Mecanicien Constructeur et Conducteur de Machines Locomotives (Paris: Chez Paul Dupont, 1851), pp. 369-370 and tables on 376-387.

These were based on Stephenson's then-current design and were only mediocre in burning the fuel in use when they came on the road. Their performance improved considerably when the railway adopted coke fuel. An extension of the wheelbase from the driving axle to the rear axle by 15.8" (400 mm) and adding counterbalancing improved the locomotive's riding qualities as well.