EMD SD-45 #4351, Cicero, IL, March 26, 1966, photo by Chuck Zeiler
This locomotive was built December 1965 (c/n 31693), and is seen here in the company of SD-40X #434, EMD's Test Car (former F-7B unit), and an unidentified prototype SD-40X. Obviously the locomotive is testing. This locomotive ended up on the IC as #7000, scrapped in June 1987, and looking at the photo of IC 7000, it seems to have acquired a larger central air intake grill.
EMD SD-45 #4351, at the Chicago Great Western locomotive facility, Cicero, IL, March 26, 1966, photo by Chuck Zeiler
Built December 1965 (c/n 31693) on order #5696, it is powered by a 20 cylinder 645E3 prime mover producing 3600 horsepower. Eventually it was sold to the IC, becoming #7000, the only SD-45 on IC's roster. It was scrapped June 1987. The unit is clearly under test, there are cables coming out of the cab window and wrapped around the safety railings along the long hood, and there is a gentleman concerned about something behind the engineers door.