I decided to start with the right-hand wall section, as that one seemed to be the most straight-forward. Upon recommendations from people on the main S-scale discussion list, I bought several sheets of Plastruct's "HO-scale, 1:100" red brick, part #PS-97. The individual bricks come out to just about exact S-scale. Neither "HO" nor "1:100" is correct in their labeling.
This extreme close-up photo shows the S-scale ruler next to the sheet. I didn't quite line up the ruler with a single brick, but if you imagine moving it over a bit, you'll find that a brick is 9" or just slightly under that. My prototype measurement of a red brick is 8.75", so this is just about as close as you're going to get. Same thing with regard to the vertical height of the brick. My prototype brick measured 2.75", and so does this Plastruct sheet; it is just a hair under three scale inches in S-scale.
I had previously done some extensive calculations to determine the size of the structure. However, when I found out that the Plastruct bricks are an exact scale version of the real thing, I decided to build the walls just by counting the number of bricks seen in the prototype photos. The Plastruct sheet material is only about 0.020" thick, so I decided to cut a mosaic and glue the individual pieces to a sheet of 0.015" white styrene. Additional re-enforcements of the wall section will need to be done later, but this allows me to cut up the sections of the wall and then assemble them around the spaces for the doors and windows. I presume this area to have been the passenger waiting area, which has a door in the middle flanked by two windows.
There is a grey-brick ledge under the windows, which I made out of styrene strips. On the left side, I fabricated the strips and then cut them at a 45-degree inside angle (against which another wall be mounted later). On the right-hand side, the ledge wraps around the side of the building (which I won't model).
I made the ledge out of four pieces of strip styrene, which is what the prototype looked like (as least from the photos I have). The top strip was a scale 4"x6" strip (with the 6" side horizontal and the 4" side vertical). Under that I glued successively smaller strips, namely 1"x4", 1"x3", and 1"x2" strips. This is a close-up photo of the ledge.
The space between the bricks and the actual window is filled in with 0.020" styrene. This is tedious work, especially considering I have to do this a number of times. I did the two side pieces (with all the odd cut-outs), and then one piece over top of both of them, so there are three pieces of styrene used here.
I then did the same thing to the window on the other side. I used the back of the Exacto blade to mark the stone cut lines you see in the prototype. These will be highlighted in the future using weathering powders.
The door area gets the same two side pieces of styrene. Note that I had to make a correction in the upper brick area (compare it against the photo above). The top section of the door area is more difficult because it has a curve to it. I determined the top of the curve by counting bricks down from the top of the door area. This was very tricky to determine and then cut out.