Concerning the drawing of a Cockerill Type IV locomotive which appeared with the above article in RECORD 8, Mr R.H. Inness raised the question of whether the return crank and connection which rocks the expansion link was omitted from the drawing. Mr C.G. Down states that this feature in Cockerill Types III and IV is situated, rather unusually, between the frames; it is not visible from the outside and hence was not included on the drawing. An eccentric on the rear axle is linked to a crank on the expansion link pivot, this despite the fact that the rest of the valve gear and valve chests are outside the frames in conventional manner. Quite why this strange arrangement was used is unknown. In the Type V, the entire valve gear is outside the frames in the normal way.

    Mr Down’s drawing was based partly on a makers’ drawing of the Type IV locomotive, and on measurements taken from Cockerill 3068 of 1924 at the Seclin sugar factory (Nord) of V. Dujardin et Fils. A close−up of the motion of this locomotive is reproduced below.

    As a point of interest, it might be noted that the worksplate in the drawing actually bears the number 3076, this being a locomotive mentioned in the forthcoming Pocket Book CF, for the cover of which the drawing was originally intended.