Bruce Hansen writes: In 1935, Erector Building Sections or more commonly termed Skyscraper parts were added to the No. 3 1/2 – No. 9 1/2 sets.
Included here is the 3 Story Apartment House – Brick Construction” front, rear and inside views. Angle girders and strips were used as the framework with the cardboard panels held in place with NT snap rivets or screws/nuts.
Pictures include the other 11 models shown in the manual. The cement construction panels generally have the angle girders on the outside of the cardboard panels while the brick construction is shown with the girders on the inside.