When the Grand Central Terminal projetc was undertaken around the turn of the century, the tracks leading to the existing station were lowered in the vicinity of the staion, probably from about 96th street south. North of there they were elevated.
When the terminal was built, tracks were lowered in the area one by one, moving from East to the west. The two photos show the tracks as they existed after lowering but before the railroad was completely decked over. In the last photo, you can see the steel framework starting on the right side of the street. The earlier photo is probably about 10 years later but before the median was completely covered over.
