Well, I can say i've been to yonkers now.
Two things: I had a professor in college who would go on long winded raves about Otis Elevator. Now, for some reason, Otis holds a special place in my heart.
As for the old
coal chutes, an alternative hypothesis: The building could predate the city's sewer system. E.g. chicago put in a sewer system in the late 19th century, and to be lazy, they just plopped it on the existing road, and many old original buildings are now about 4ft below street level. Obviously, I don't know Yonkers' history, but just tossing it out there. A good clue would be many other buildings in the area with similarly sunk windows.
Or its just a coal chute and I'm trying to sound smart.