 Around 1930, the question of maximum axle loads for locomotives was thoroughly investigated by the Mechanical and Civil Engineering Departments of the SAR.It was found that, along with some other locomotives, the Class 14C had a rather severe vertical hammer blow effect on the track when running at speed due to an undue proportion of the reciprocating parts being balanced.Modifications were accordingly made to the Class 14C to allow some of them to run on track.