Note that in the ebay ad, the seller did give the dimensions of the buildings. The one house was described as being 6-1/2" high. A quick "rule of thumb" for working out HO dimensions is to figure 1 real inch is about 7 HO feet. So a house 6" high would be about 45' high. A real two-story house would be about half that big so it's clear the model isn't HO size, but a larger scale like O (HO is "Half-0" by the way.)