The D, C, and B yards, among others, can be found on this roadway map.
Note that north, the general direction of this tour, is oriented in the down
direction. Despite its upside-downedness for tour purposes, the map can be
handy for understanding the complex layout here.
For future reference, the key features are the "Metropolitan Sub-Division"
running south-north through the middle, adjacent WMATA's "Metro Shop Tracks"
that are far more numerous than depicted. Also note the "No. 1 Main" and "No. 2
Main" curving from/to the east (left); they connect with the ex-B&O Washington
Branch, now CSX Cap Sub. All of these are shown in the photos below.
Roadway Maps like this, and lots more cool B&O history materials, are available from
The B&O Railroad Historical Society.
The next photo looks down the map from its top from near the word
Avenue toward the E Yard.