This is Fallers early watermill model 24 from 1950. 

You could only buy it as a ready-made and it was one of the first models with a working water-wheel. It was operating on a 15 volt little motor which was constructed inside the model. Faller was ahead of its time with this model.

Over the years the looks of this model changed very little. On this early model everything was done very minimal.

On the roof there was no chimny till 1952  The wooden bridge over the water had no fence.The shutters did not have a lozenge-shape in them as faller for the first time put into practice in 1952 . The covering of the roofs was done with thin cardboard in which on the main roofs horizontal carves were made. The stairs before the front door only had two steps. And last but not least the wiring was connected outside on a plug. From 1952 the covering of the roof was done with painted toilet paper to give it a better look.

Faller used till 1959 the picture of model 24 in its catalogues. Also in the catalogue from 1953 the same picture is used but it is more sharp and in my opinion there is no fence near the wooden bridge .  In 1951 a fence was added , the stairs before the frontdoor got three steps and a paper Faller mark with the number 231 or 232 (without motor) was added.

The use of real little stones in this model is a wonderful and very bright idea.

Some 1950 models had an ink stamp with the number 9B. Till now nobody has an explanation for it !

The factory of Faller was and still is situated at the Kreuzstrasse 9 in Gütenbach Germany.

Perhaps this explains the number 9 . But I have no explanation for the letter B .  It could be an inspection number.