Bob Courtney posted this request for information on the Yahoo KCS Discussion Group (sorry, don't have the address) and got these replies.

The photo in question was taken in Heavener just northeast of the engine house looking to the southwest. Tut Bartzen

Number 71 is an F7, 95 is an F3. The black unit behind 95 is one of the GP7's still painted in the black scheme. Numberboards on the front start with a 4 and the last digit visible on the cab side appears to be an 8. This would make it the 4158. It's original number would have been the 158. Question to ask..... When was it renumbered to 4158 from 158 and when was it painted white? The 4162 still has it's high nose front, so that definitely makes this a pre-1983 picture as it was rebuilt with a chopped nose after the wreck in Pittsburg, TX in '84. It is also post 1954 as it no longer has the GP7 louver on the hood and the panels under the cab since it was rebuilt from a GP7 into GP9m after its first wreck in 1954 by EMD. Casey

Chuck's comment: As stated, all information was a guess. I chose Pittsburg because I knew there was a shop there and the locomotives looked like they needed shopping more than servicing, but the roof vents on the shop building are unusual for the KCS. The 95 is a upgraded F3, according to the book, Kansas City Southern In The Deramus Era, by Louis A. Marre and Gregory J. Sommers. It was delivered in 1948 as F3 58A. In 1957 the 58 A-B-B-A set was broken up and 58A was renumbered 58, later renumbered to 95 before the KCS settled on four digit numbers for the F-units. Note 36 reads:

L&A 58A rebuilt to F7 specifications 12/31/53; renumbered to 95 at Pittsburg 5/68; renumbered to 4052 at Pittsburg 4/3/78.

As for the dark GP7, I assumed it to be an MP unit (but it lacks the MP chevrons), so KCS 4161 would be my guess. I looked at a closeup of the slide but could not accurately make out the number so I made no comment in the original post. Another determining factor to help pinpoint the date is the repaint, renumbering, or retirement date of 71. UPDATE: I received an email from Paul Strang with the following; I don’t recognize the photo and I don’t think I’ve ever seen the power split up that way. This shot might be by Steve Laser. He went there at lot right after he got out of the Navy and I ended up processing most of his stuff. This photo is at Heavener. The Wye track on which 71 was shot (in another slide) is the track in the foreground. The Fort Smith Dodger rated 95, a switcher, or a GP7/9. The AW (Arkansas Western branch to Waldron, AR) required two F-units as the max speed was 10 mph and there had to be enough power to climb the small grades w/o being able to get a run at them. The South Local had two GP30's and the North Local had two GP7/9 at this time. Mena had a GP for a switcher. It would often come to Heavener on weekends for service. That probably explains one of those units.