OECM 2-8-2 Locomotives in Morocco

Class 141 A1 (Locobase 15602)

Data from "New 2-8-2 Type Locomotives for Moroccan Railways", Railway Gazette (26 August 1932), p. 257. See also Jacques Gandini, "Les locomotives a vapeur", Les Chemins de Fer de Maroc website at [], last accessed 14 November 2013.

The great success of the Etat Mikado design that appeared in 1921 (Locobase 15577). When the Moroccan Railway sought a powerful locomotive, they supplied the Polish builder Chrzanow with plans and asked for duplicates. While keeping the Belpaire firebox, cylinder size, and driver diameters, Chrzanow decreased the number of small tubes and increased the diameter of the flues holding a new superheater design. As can be seen, the larger superheater provided an impressive percentage of total heating surface area.

Piston valve diameters measured 350 mm (13.75 in) and offered a 156 mm (6.17 in) maximum stroke. A Dabeg "feed-heating" pump (probably best thought of as an exhaust injector) added to the boiler's readiness to steam and a Kylchap blast pipe enhanced exhaust performance.

(NB: As per Continental practice, evaporative heating surface was calculated from the fire side (interior diameter). Using the 50 mm/1.97 in tubes and 140 mm/5.51 in diameters, tube and flue heating surface area amounted to 173.3 sq m/1,865 sq ft. With the firebox area, evaporative heating surface area was 188.4 sq m/2,027 sq ft. Locobase uses the external diameter to simplify comparisons with British- and American-influenced locomotives.)