Received the following via email.
Back in the early '80s it was my good fortune to be invited up to see the inside of COLA Tower in Columbia, PA. Unfortunately I didn't record the actual date of when this photo was taken. This visit proved to be both an interesting and informative with the tower's second shift operator. Cola Tower's control began at TOME, 4.5 miles from Perryville (MD), plus ten more interlockings between there and COLA, and three interlockings to the west. Those machines seen to the left in this image print out readings from hot box detectors in the field. Once the Port Road got CTC, the windows were bricked over and the tower was turned into essentially a large relay case. The blue and white "COLA" sign still looks good as it hangs on the tower's side to this day.