Ah, thank you Jason, I must have been very tired when I read the article, it says 1:12 but I managed to miss it 
In general I think there are enough measures on the drawings to re-scale them, but I think it is always useful to be able to check at specific places without measures and then a scale is nice to have, it simplifies. For my purposes I have to re-calculate anyway, from 1:12 Imperial to 1:87 metric. It will probably be a fiddly little thing but one with a lot och charm as those older industrial items often have. It must be due to that at the time the designer bothered not only about function but also about the looks and that create items with their own character I think.
Furthermore, such items are easy to use in just about any layout in Europe as the things were traded all over.
Neil, PM coming …
BR
/Peter