ALCO Demos: #102 and #103: no information on these two units.
HH660: #105: had a Wabco B-6 horn mounted on the engineer’s side of cab next to hood, pointing forward. #116 (2nd): had a Wabco B-6 or A-6 (horn A) mounted on the engineer’s side on cab next to hood pointing forward.
S-1: #117: had a Wabco B-6 or A-6 (horn A) mounted on a bracket centerline of cab just under roof overhang, photo dated 8-68.
S-2/S-4: #150 thru #158: all units had Wabco B-6 or A-6 (horn A) mounted on a bracket on the front of cab centerline under cab roof. #159: had a Wabco B-6 or A-6 (horn A) mounted on cab roof centerline, toward the front of the cab. #160: had two Wabco B-6 or A-6 (horn A) mounted in the centerline middle of cab roof, one pointing forward and the other pointed in reverse. #161 thru #167: were the same as all other S-2s and S-4s.