Remaining active towers...

Recently, Kensington interlocking on the electric district was cutover to Metra's CCF (Consolidated Control Facility), and the tower is no longer manned. Off the top of my head, these are some of the towers that are still in use, with the intersecting roads in parantheses, where applicable:

UP: CY (Clybourn), also controls Deval & Mayfair crossings.

UP/W: JB tower, West Chicago (EJE)

Milw/NCS: A2 (UP), & A5

Milw/N: Rondout (EJE)

Heritage and SW: 21st St (CNIC, ex-IC, also referred to as IC Iowa)

Rock: 16th St. (CNIC), Gresham, Blue Island, and UD tower in Joliet (UP/BNSF)

Electric: 67th St.

So, that's 11 so far. Or could be; not sure if the towers at Gresham, Blue Island, and 67th St. are still manned. Again, this was just off the top of my head; corrections welcome, and feel free to weigh in if I've missed any...

Confirmed via a trip to Blue Island a few days ago that the tower there is indeed an actively manned facility, staffed by Metra employees. An interlocking operator is also stationed at Gresham too, although only part time on weekends...

Blue Island is indeed still in use, all trains using the branch need permission before proceeding past Vermont Street.