Southern 4113-Stealth Unit

[SSW9389]

Check out this linked J. Parker Lamb photo of Southern 4113 leading a train through Meridian, Mississippi. https://www.flickr.com/photos/railphotoart/28286531885" onclick="window.open(this.href);return false;

I'm exploring the possibility that this unit, Southern 4113 is a wreck rebuild. And that in the photo it is no longer an FTA, but an F3AM. It fits the pattern of a stealth unit that's been hidden for 70 years.

Ed in Kentucky

[Allen Hazen]

I've seen suggestions that Southern upgraded some of its FT units. (A photo caption in an old issue of "Trains" described a Southern unit as an FT rebuilt to F7 standards.) This would, I guess, have been more difficult than upgrading later F-units (F3 to F9, for example): postwar F units had a common layout, making it possible to remove components and insert new ones in their places: the FT was different enough to make this sort of "modular" modification difficult. Or so I've read, perhaps in one of Preston Cook's articles on F units in "Railfan and Railroad."

The unit in the photo has four exhaust stacks, typical of an FT. (I think all post-war F units were built with two-stack exhaust systems… I'm not sure why, given that MP's experience was that a four-stack "liberated exhaust" increased power noticeably, and that ICG's "Paducah Rebuild" Geeps had 4-stack exhausts for that reason.) Which suggest that it had, when photographed, the original engine.

[SSW9389]

"Yes, that locomotive in the photo certainly looks like the entire cab structure of an F3 has been installed, complete with the F3 front truck center pin." email just in from W. A. Cuisinier.

[Allen Hazen]

Shows how bad my spotting abilities are! I counted the stacks, but didn't notice the carbody form.
This combination makes sense, though: I'd guess the original unit had a wreck that left it basically a write-off, but internal organs (engine, main electricals) that could still be transplanted. So Southern, counting its pennies, had the usable FT works installed in a new carbody. At a guess, this gave them a unit (90% as powerful as a "real" F3) for less than half the price of a new F3. Carrying it on the roster as an FT makes sense in two ways: (i) in terms of performance and tonnage rating, it was still an FT, and (ii) by value the majority of its parts were FT (going, for the latter judgment, by the rule of thumb that a diesel-electric locomotive is, by value, one third diesel engine, one third electrical system, and one third "locomotive mechanical parts").

If my recollection of an old "Trains" photo caption is to be trusted, Southern (probably some years later) decided that engines, etc, wore out faster than carbodies, and had new engines put into at least some FT carbodies. That would produce a unit that (unless you count the stacks) would LOOK like an FT… but which I think it would be reasonable for Southern to classify as an F7.

Thanks, SSW9389, for bringing this up and posting the photo! It's an interesting case that illuminates the complexity of real-world locomotive use and history.

[Allen Hazen]

Aargh! Just looked at the photo again: four portholes. So it isn't a whole new F3 carbody, just the front end. (Which makes sense if the damage in the wreck was a crunched front.) So the economic case for rebuilding was even stronger: you get to use the internal organs AND the rear two thirds of the "locomotive mechanical portion."
…
Later F-units, in head-on collisions, tended to buckle behind the cab. (Supposedly a safety feature: the carbody behind the crew compartment was energy-absorbing, so the crew wouldn't be as likely to be crushed. Does anybody know whether this was an intentionally designed safety feature, or just a fortuitous result of other design decisions?) If FTA units buckled the same way, a serious head-on would ruin the forward potion of the frame, so EMD (I assume) in rebuilding would need not just a new cab, but would also have to graft on a new forward frame to PUT the new cab on. Which would explain why front truck centre pin is in F3 position rather than FT position.

(??? I'm out of my depth here. I hope Win Cuisinier will consider e-mailing you some more comments!)

[SSW9389]

I'm looking for a wreck photo to determine the extent of the rebuilding. It is a very early F unit rebuild.

[SSW9389]

I found a photo online that shows a rebuilt FT booster unit lashed up behind the 4113. The booster has a fifth porthole at the overhang end of the unit, which is opposite of as-built practice. A rebuilt Cotton Belt FT booster has the same pattern of fifth porthole over the overhang end of the unit. Normal as-built for the fifth porthole is front right. The rebuilt Southern booster unit and the Cotton Belt unit are both back left.

Ed in Kentucky

[SSW921]

I found this 1947 photo of the 4113 last week. It's not a full profile, but is a better angle to see how this unit is different. Take the F3 challenge, download the photo from WorthPoint. Draw a straight line from the front corner of the cab window directly to the rail. Notice where that line intersects the truck frame. https://www.worthpoint.com/worthopedia/ ... 3003983896
Ed in Kentucky