This is a detail view of the grille tile support structure.

The grille tiles are attached to a 4x4 black plate, and a 1x2 plate is attached to the back of the black 4x4 plate. Note that the white plate is connected to the 2^nd row on the back of the black plate.

The white 1x2 plate is connected to the 1x1-with-side-loop plate, and this holds the grille tiles in place.

In order to get the bricks to line up correctly, the 1x1-with-side-loop plate is one plate and a brick above the floor. This makes enough room for the 1x4 tile to fit between the grille assembly and the floor.

When grille tiles are attached like this they are not perfectly flush with the outside of the car like they are when 1x2 hinge bricks are used (see the EMD SD40-2 page for this one). Since I hope to put a compressor inside the compartment, the extra space was more important than making certain that the tiles were flush with the outside of the car.