@mihai.s pointed out some drawing issues that explain why faces aren’t forming.
In the spirit of helping you improve your model:
I see some peculiar and possibly excessive nesting of groups and components. Have a look at the Outliner window and watch what happens as you select various elements of the hierarchy. Often there seems to be no change as you descend deeper into a nest, suggesting that a level of nesting wasn’t really necessary. Combined with your use of layers, this leads to confusing results that make it hard to work with the model.
For example, if you turn off visibility of either the BRIDGEhangingSTATION or the MALLincorporated layer, you get the result below because of how layers are associated with nested content. Also, there seem to be some possibly misplaced edges in the stuff that remains visible?