Below is information received from Everett and a little from Virgil. It was coming fast and furiously and I was trying to keep the engine shots, some his, some mine, straight as he was feeding the info out. Some may not be synced. It is a lot to assimilate. It is a big answer to a seemingly simple question. Take a deep breath and dive in.
A "cab" unit is the old style where the actual locomotive body covered the entire locomotive, and was built of truss construction (like a bridge) so that the body actually contributed to the strength of the engine. A "hood" unit is the more modern type of locomotive where the frame is the entire strength of the locomotive, and the "hood" just sits over the engine.
A couple of examples from my collection of Gulf Mobile and Ohio photos will illustrate the difference.
In the enclosed photos, #801B is an EMD F-3 locomotive, 1500 hp, built in 1946,
and #811B is an EMD F-7 locomotive, 1500 hp. built in 1949.
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It was this type of locomotive that the Santa Fe chose to rebuild. They are "cab units".
Santa Fe 287 is one of their locos that was the type that was rebuilt.
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# 640 is a 2500 hp EMD GP-35 built in 1965. and
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#711 is a 2000 hp EMD GP-38 built in 1972.
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These are "Hood units" #711 is the same general type of loco
as the Louisiana & Delta 1700 series engines.
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Finally, #2358 shows one of the Santa Fe units after
rebuilding in to what is called a "CF-7" type unit.
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It is one of the same series of engines that the L&D 1500's
come from,
although as I pointed out, the 1506 has a different style cab.
*That is all made clear in a paragraph down this page.*
For the above 1504, he added: You are correct, it is 1504 that
has the new style cab which was the last style that the Santa Fe
built of the CF-7's. The square thing on top of the cab is an air conditioner,
and I think that is one reason that they went to the square cab, so they
could add the AC. You can still tell that it is a CF-7 by the short nose
and the "Whalebelly" stiffeners added to the middle of the frame above
the fuel tanks.
He further states:
1502 had the old style cab.
(They were all orange engines to me).
Everett added: Mz Allegheny is definitely a CF-7 by the cab
made from the old car body, and the added strength to the frame members
on the side.
The older versions actually recycled some of the
old car body in making the engine cab.
Back to me, thanks Everett.
So, I'm guessing the two engines out at the west yard in
Lafayette would fall under the same design as the L&D 1500's.
I'm waiting on his blessings. He hates it when I wing it and
fall from the sky causing confusion and a feathery mess.
Everett explains these 2 below, don't worry, the pictures
will be copied there to support his descriptions.
I just found what Everett had sent me earlier. It was on the last
published page, duh on me. I'm definitely losing it. He is
probably shaking his head and figuring I'm hopeless because
I asked him to "clear up" something he had made clear. Here's
his earlier attempt at bridging the gap between my ears.
***"Ms Allegany, 1502 and 1504 are part of a unique breed of locomotive. It is called a CF-7 and they are about the last of the lot".
DON'T FORGET TO VISIT EVERETT and all his merry guys and gals at the SOUTHERN FOREST HERITAGE MUSEUM Click here to visit their site. Don't stop now, there's more.
Below taken at Lafayette at old Alexandria Branch Junction.
This is 1708.
The 1708 is a "Paducah Rebuild". At the same time as the Santa Fe
was rebuilding their old cab units, the Illinois Central was rebuilding
their old hood units. They rebuilt units like the 9084 in the picture that
I am sending, into units like the 1708 by chopping off the high short
hood and making a low nose, so that the crew had a view like most
engines do now, and they added new control systems, and housing
for paper air filters on top of the long hood. They also increased the
horsepower as well.
Below is Everett's shot. I'm thinking that engine is sitting on a turntable.
We'll see. Yes, he just verified that. "It is on the turntable at
the old Bloomington, IL engine house. All is gone for about
30 years now, including the railroad.
The "Mountain Laurel" engine that used to be seen in Lafayette for thepast 10 years was also of this type.
This shot was taken on the Pesson Branch, Port of Iberia.
Seen at the Lafayette, La. west yard.
BN 2899 is either a GP-35 or a GP-38 as you can see that it resembles both of them, and in fact they use almost the same body (I never have been able to tell them apart) The major difference is that the GP-35 has a turbocharger and the GP 38 does not. Actually, applying that logic, 2899 is a GP-35 in that the there is an exhaust stack for the turbocharger behind the first bulge on the top of the hood behind the cab. It is followed by the dynamic brake housing and fan, and then the two radiator cooling fans, In front of it, is the housing for the some of the electrical stuff above the main generator.
Shot at Lafayette yard.
Shot at Lafayette, La. yard.
Speaking of the above engine.
The 6957 now is an entirely different type of loco. It is called an SD-40.
At one time it was the most common type of locomotive in north America,
but now most of them that remain are pushing 30-40 years old themselves.
It is different in that it has 3000 hp, and is bigger and longer than the
other types that we have been talking about. Instead of two, 4 wheel
trucks (called a B-B type), it has two 6 wheel trucks, all powered, and
is called a C-C type. It will pull twice as much as the L&D engines,
but it is a lot heavier, and harder on their track so that they cannot use
it on their light rail. It is the type predecessor of all of the big modern
4000-4500 hp engines that the railroads use now. You will notice that
they almost always have 6 wheel trucks and are much bigger and
heavier than the L&D engines.
Shot at New Iberia Depot.
.
He adds: 1500 is another CF-7, Utah is a GP 38 (no turbocharger exhaust stack)
That's convenient, 1500 and Utah are above. Utah is below. I had just posted the
UP engine to show the differences in drives and size. Bottom shot at Lafayette yard.
Whew, time for a break. I'll find a pic of 1707.