Question here about the history of RBe push-pull sets for the purposes of correct formations on a model railway.
This isn't very long ago, but memory can play tricks.
From memory, when the S-Bahn Zürich first opened, many lines used RBe uniots coupled to two EWI or EWII plus a BDt. These four car sets could be combined into longer 8 or 12 car sets.
At the time they were still in green livery, using the Swiss shield rather than the SBB logo.
Then as conductors were phased out, some modifications were made, including the removal of exterior grabrails and shunter's steps so passengers couldn't jump up onto a moving train. Is this correct?
Later a program got underway to modernize these trains. Folding doors were replaced by swing doors and at the same time the green livery was replaced by the NPZ style blue and white with yellow doors and the interiors also modernized with the imitation red or green leather seat covers replaced by moquette in 2nd class, and the luggage racks over the seats replaced by luggagte racks over the windows. Changes in first class were more subtle, it mostly it just being the seat moquettes that got changed. Some of the toilets were removed and repalced by bicycle areas.
Now my second question is about the transition period here. I seem to remember that modernized and unmodernized vehicles would run mixed within the same trains. So you might get, say, a green RBe and then a blue/white B and then a green A and then a green BDt, or something like that all in the same 4-car set. Is that correct? Does this mean the door controls were compatible between unmodernized and modernized units?