This model from 1928 is of a Mobile Electric Crane is a model of the mobile
type of crane that would
have been a common sight in British railway goods yards and industrial
sites from the 1920s
until the 1950s. When I was a small lad our local British Railways
goods yard (Gravesend East) had one such
crane in the 1950s. I remember it noisily and slowly
trundling around on solid rubber tyres.
The model itself is a fairly accurate representation of the prototype, a 6 tonne Ransomes and Rapier petro-electric crane. The prototype crane, as in the Meccano model has front wheel drive with rear caster steering. Petro-electric refers to the fact that there is a petrol engine driving a generator that provides power for electric motors one for each of the operations of the crane. However the model is poorly designed with regard to the operating mechanism which is operated from a single Meccano motor in this case the E20R(S).
Shown below is an illustration from the original leaflet.
The monochrome picture below is taken from the Super Model leaflet shows the prototype of the crane lifting an early wooden shipping container in a railway goods yard circa late 1920s.