This model is taken from the Design 3 set manual.
It is alright as it is but could be better. This is due to a number of errors by the French in the manual.
It is not at all easy to build any of these models - they need a lot of skill to make them work. The builder used photos from the Meccano website to help build this model.
It is driven by a 3V motor and works well, if built with care.