This ventilation intake is located at the midpoint ofthe northbound tube. Vane axial
fans shoot exaust through grates in the 4th St. sidewalkdirectly above.
This smaller intake is located at the midpoint of thecenter single-lane tube.
Strangely, there is not an intake in the southbound tube,even though it is
of similar length to the others.
The tunnel exhaust grates -- the bottom grate is for thenorthbound tube and the top for
the center single-lane tube. There is apparentlyno grate for the southbound tube.