The modified corner bracket
from left to right: Ballenberg, ToyTrain, D4016
slipped into the slots on the car…
Next I flattened the tubing and the brass rod, squeezed it in the vise, cleaned up with a file, drilled the holes, soldered the joints and then cleaned them up.
A note on the drilling: the 1.2mm drillbit is perfect. Doing it freehand with the Dremel without centerpunching the positions is not the real McCoy, but it works. Since this was just a “let’s try this”, it means that even without a milling machine it will work. The other platform railings - I need about 30 - will be done on the milling machine with straight alignment and almost perfect pitch. 
What is still missing is the handrail for the walkway from car to car. That needs to be bent and I’ll need to stress relief the brass tubing first - heat it with the mini torch - for easier bending. To be continued.
Milling the windows
Plunge cut into the wall with a 1/4" cutter and then mill.
Cut to size with a file. Next step will be touching up the corners with an Exacto knife to get them nice and sharp. To be continued.
Glass for the windows
In this case I use some kind of Plexi, measure the window openings and then mill the glass slightly larger. Then each pane gets filed to the proper size (tight fit).
To get rid of the annoying reflection from the part which gets glued to the wall I use a felt pen and colour that surface. To be continued.