I am not much of a railfan, but an old post got me thinking, and suddenly I found myself on a 5 hour search for these. Then came across some awesome information.
AFAIK, the siren community has only known of the 2 UP Locomotives that had the 1003's installed for Testing - UP 6918, and UP 6924.
Turns out, this program consisted of 6* total Locomotives.
All these are Union Pacific engines:
#3049 SD40 Is noted to be an electronic siren capable of Wail, Hi-Low-Yelp. ~No photos exist to my knowledge. Installed 8/75 ~ Removed 1/79
#1400 SDP35 Installed 4/78, Removed 3/79. 1003
#1402 SDP35 Installed 4/78. Removed 3/79 1003
#1408 SDP35 Installed 6/78 Removal unknown.. Multiple Air horn arrangement.
#6924 DDA40X 4/79 Siren removed from 1402 installed on 6924. 1003
#6918 DDA40X 3/79 Siren removed from 1400 installed on 6918. 1003
Siren remained on unit #6918 and #6924 until unit retired(per a document- photos don't match the statement).
The idea behind the Siren implementation was to warn track maintenance and repair crews of incoming trains.
I believe these are the first time the siren community has seen these 1003's in such quality.
Thank you to Raymond D Woods Jr for originally posting the picture of the UP 615 with a visible horn behind it in a picture from Yermo,Ca from 1983.
*Excerpt from UP timetable*
Here is the site I was able to get the technical information from https://utahrails.net/up/up-loco-features.php.October 26, 1980
The following comes from Union Pacific System Timetable No. 4, October 26, 1980, Special Rule 1092, page 149:
Siren installed on unit 1400 operated by a single throw toggle switch, siren on unit 1402 operated by a single push button and sirens on units 6918 and 6924 operated by a single slide pole switch. On all units so installed switches are on the instrument panel in front of the engineer labeled "Siren."
It is intended this siren be sounded for an emergency only when approaching and passing gangs or workmen who have not noticed or heard regular horn warning. Sirens are not intended to be used in cities, towns, municipalities or at grade crossings, except in emergencies.
When sirens are used in an emergency situation, radio report of the incident should be made by engineer to dispatcher giving all necessary details.
(This rule first appeared in System Timetable No. 3, dated March 9, 1980, and remained in System Timetable No. 7, dated July 17, 1983. The siren rule was *not* in System Timetable No. 8, dated November 20, 1983.)
Pictures came from old forums, defunct websites, fb groups, etc.
Hope you guys enjoy this, spent 4-5 hours this morning digging through literally probably 5000 pictures. My head hurts.
Cross posting to FB.
-Rhett