EMD SW1/900m: #106 thru 115: had a Wabco B-6 or A-6 (horn A), usually mounted center of cab under roof overhang on a bracket. #107 (2nd): had a Wabco B-6 or A-6 (horn A) mounted on bracket centerline under cab roof overhang. #110 (2nd): had a Leslie S-1 (see horn D) mounted on a bracket centerline of cab under roof overhang.
EMD SW1/NW1: #118: had a Leslie A-125 (horn C) mounted centerline of cab under roof overhang on a bracket. #119: had a Wabco B-6 or A-6 (horn A) mounted the same as on the #118. #120 (1st) thru #130 (1st): all of these switchers had a Wabco B-6 or A-6 (horn A) mounted on a bracket centerline under cab roof. #120 (2nd): had a Leslie S-1 (horn D) mounted in the same place as on the #120. #121 (2nd): had a Nathan M-3 (horn F) mounted on a bracket centerline under cab roof. #122 (2nd): also had a Leslie S-1 (horn D) on it. #123 (2nd): no information. #124 (1st) and #124 (2nd): had a Wabco B-6 or A-6 (horn A) mounted the same way. #125 thru #127 (2nd): no information. #128 (2nd) – #130 (2nd): no information.
EMD NW2/DRS-4-4-15: #180 thru #186: had Wabco B-6 or A-6 (horn A) mounted on a bracket centerline under cab roof. #181: had a Nathan M-3 R1 (horn G) mounted on the roof in the centerline towards the front. Photo dated 5-72.
EMD SW7: #220: thru #224: all came with Wabco B-6 or A-6 (horn A) mounted centerline of cab under cab roof on a bracket. #220: had a Nathan M-3 R1 (horn G) mounted on the centerline of cab roof, toward the front.. Photo dated 4-69 #221 or #222: no information. #223: had a Nathan M-3 R1 (Horn G) mounted the same as on #220. #224: had a Leslie A-175 (horn C*) mounted the same as the other SW7s. Photo dated 8-73.
EMD SW8: #250 thru #259: all were delivered with Wabco B-6 or A-6 (horn A) air horns. All were mounted on a bracket on the centerline of cab just below the cab roof overhang. #250: a photo dated 10-74 shows a Leslie S-2 (horn D*) mounted the same place. #254 (photo dated 3-74), #255, #257 (photo dated 11-74), #258 (photo dated 1-75), #259, #260, #263 (photos dated 3-66 and 10-69), #264 ( photo dated 10-69), #266 (photo dated 5-66), #269 (photo dated 4-73), #271, and #273 (photo dated 11-72). All of these units had Nathan M-3’s (horn F) mounted the same as on the rest of the SW8s. #261, #262, #265, #266, #268, #270 and #274: I think these units had Nathan M-3’s (horn F) mounted the same as on the other SW8s, but hadn’t seen any photos of these units. #275 had a Leslie A-175 (horn C*) mounted the same as on the other units. Photo dated 7-72. #276 had a Leslie A-200 (horn B) mounted the same as on the other units. #280 thru #292: all had Nathan M-3’s (horn F) mounted the same as on the other units.