External difference U30C vs. C30-7?

[Steve F45]

Trying to figure out if there is any external differences between the above to engines? Or even the U36C vs. C36-7?

[westr]

Probably the easiest spotting feature for a Dash-7 is that the long hood abruptly widens by about a foot at the exhaust, resulting in a "step" a few inches deep on each side, about four doors ahead of the radiator section.

[MEC407]

Correct, and this difference applies to all Dash-7 locomotives.

Specifically in regards to the U30C, it doesn't have the radiator "wings" that the C30-7 has, so that's another way of telling the difference. This also applies to the U23B vs. B23-7... -7 has wings, U-boat has no wings.

U36C and U36B both have wings, so you have to look for the "step" in the hood, as westr mentioned.

[westr]

Thanks MEC407. The radiator wings on C30-7s had slipped my mind. Since you mentioned that U36s have radiator wings like the Dash-7s, I'll also add that U33s are externally virtually identical to U36s.

While we're on the subject, another thing to watch out for with U30s and B30-7s is that U23s look almost identical to U30s and B23s look almost identical to B30s. In both cases, the difference is that 30s have 8 tall doors for the engine compartment while 23s only have 6. As mentioned, the Dash-7s have the "step" and radiator wings while the U-Boats don't, so telling a U30C from a C30-7 is probably easier than telling a B23-7 from a B30-7. I don't think a C23-7 was ever built though, so we get off easy there, but there were some C36-7s that looked just like C30-7s, and some that looked almost the same, but had more openings under the radiator wings. Fortunately, the C36-7 was pretty rare compared to the C30-7, and most of them had large boxes above the dynamic brakes behind the cab protruding above the roof that C30-7s don't have, so you're not very likely to run into one that will trick you.

[Allen Hazen]

About "wingspan"...
Looking at pictures, it seems to me that the top of the radiator compartment-- the screened roof over the radiators-- is a bit more arched (& higher LOOKING) on the U33/U36 models than it is on the Dash-7 models.

Another spotting feature for distinguishing U30C from C30-7 is the air intake for the central equipment blower, high on the side of the hood behind the cab. Look at a few photos (of both sides, since I think that on one model the two sides are not the same...): I don't want to try to describe the difference. On the U30C (as on all "classic" U-series models from 1966 on) the intake grill is divided into three parts: on Dash-7, not.

Another difference noted (in "Extra 2200 South") when the Dash-7 line was introduced was in the air vents on the left side of the short hood (low-short hood units): the U-series hood had a very short column of vents, the Dash-7 a taller one. This, however, is not a reliable sign: looking at photos of Conrail GE units I have seen many with the "wrong" nose vents. I assume this is because of use of "wrong" parts in repairs.

There are subtle differences in the truck frames that can ROUGHLY correlate with the age of the unit (Adirondack frames on U28C and early U30C are particularly recognizable from the pronounced "shelf" over the center axle, eliminated in later versions), but again this is unreliable as trucks get exchanged in maintenance (and probably some early U30C were traded in on late C30-7 with trucks re-used). "Model Railroader" had an article on the C30-7 that noted this (and advised modelers to get photos of the particular unit they wanted to model-- they should have added that the photos should be dated!).

[Steve F45]

I probably should've added this to the original post. I was asking this question for a modeling project. I have a Atlas U34CH and wanted to get a few more uboats. But i've seen some Dash 7's that are pretty cheap. I was going to get maybe a c36-7 and paint in EL or NJDOT colors and pass it off as a U36C. Now is the U34CH similar to the design with wings?

[westr]

I see: you want to get a C30-7 and use it as a U34CH or U36C. The U34CH was basically a U36C with HEP added, externally its virtually the same as a U33C/U36C (Atlas used the same shell for all three). All have radiator wings similar to the C30-7. Ideally you should use the U33C/U36C/U34CH; the C30-7 will have a number of details wrong as mentioned in the previous posts, including grill/louver placement and most noticably the widening step at the exhaust. It up to you to decide if that's acceptable to you.

[Steve F45]

Well i dont want to use a c30-7 shell. I was going to use an atlas shell. At the time of the post i didn't know what the differences were, hence why i asked. But once the first reponse said there was a wide spot by the exhaust and a step i figured the uboat shells would work. I do appreciate all the responses from you guys for answering my questions.

Now maybe you can answer this question that has been bothering me that I can't figure out. What is the difference between the AC4400 and the ES44AC?

[westr]

Glad to help. Now for the AC4400 vs ES44AC. First off, though they look somwhat similar on the outside, especially from the front, internally they are very different: The AC4400 uses a 16-cylinder engine while its replacement, the Evolution series ES44AC uses a 12-cylinder to produce the same horsepower, and is Tier II emissions compliant. Similarly, there is a ES44DC that replaces the C44-9. The ES44DC and ES44AC are very similar looking. There are a lot of subtle differences between the ES44AC and the AC4400 and I don't know all of them, but the most visible differences are in the radiator sections, which are quite different. The ES44AC has a much larger radiator section that overhangs slightly in the rear, and the wings have two distinct sections, front and rear, that are visibly different. The grills/louvers under the wings are also different. Its hard to describe, so I'll give you some links to pictures:

AC4400CW
http://myweb.msoe.edu/~westr/Pictures/U ... 205867.JPG
http://myweb.msoe.edu/~westr/Pictures/U ... 205685.JPG

ES44AC
http://myweb.msoe.edu/~westr/Pictures/U ... 5248-3.JPG
http://myweb.msoe.edu/~westr/Pictures/U ... 205398.JPG

ES44DC
http://myweb.msoe.edu/~westr/Pictures/B ... 7699-3.JPG
http://myweb.msoe.edu/~westr/Pictures/B ... 7759-1.JPG

Union Pacific has managed to confuse the issue even more, by calling the AC4400 as both C44AC and C44ACCTE (depending on if they have controlled tractive effort or not) and calling the ES44AC the C45ACCTE (even though it is only 4400 hp)

Now, I figure this will lead to the follow-up question of "How do you tell the ES44DC from the ES44AC?" Here are the differences I've noticed: In the dynamic brake section behind the cab, there are 2 grills on each side: on the AC they are close together while on the DC they are further apart. Also, the large inverter box on the left side has a couple removable panels in it on the DC that are not on the AC (or the AC4400), and the AC has another box mounted on the walkway just behind the inverter box that the DC doesn't have, and the handrail is altered accordingly. (this box is also on some AC4400s) These differences can be seen in the pictures.

[trainiac]

There is a whole host of minor differences between the U30C and C30-7--in fact, they hardly share any exterior sheet metal. In addition to the differences already mentioned, compared to the U30C, the C30-7 has additional doors behind the cab, different access panels under the cab, a longer radiator compartment, different doors under the radiators, center hood doors moved forward, different handrail stanchion spacing, different central air intakes... Plus probably a few more that I forgot to mention. None of these are obvious when you see one passing by, since the carbody outline is the same. But it does mean that for a entirely accurate model, the U-boat and Dash-7 cannot replicate one another without major surgery.

As for the ES44AC vs. AC4400CW, aside from railroad-specific details, they are pretty much the same under the walkway, and from the front end to the front section of the hood behind the cab. Beyond that point, the ES44AC has a shorter central air intake area, 6 tall hood doors per side (instead of 8), 3 doors under the exhaust stack (instead of 4) and a much longer radiator compartment that has two roof profiles and notably thicker "wings" that extend to the rear of the hood. The main radiator intake is farther back, and the rest of the intakes have been rearranged, with a bunch of additional doors and intakes ahead of the main radiator intake.

The differences between the ES44DC and ES44AC are much more subtle and are concentrated in the hood area immediately behind the cab. The ES44DC has different X-panels and hatches on what would be the inverter cabinet on the ES44AC (left side behind cab) and different dynamic brake intakes occupying the first and third panels with the center one blank. If you're really nit-picky, you'll be able to spot the ES44DC's thicker and more numerous DC traction motor cables under the left walkway.

As for the ES40DC, aside from phase details and NS specifications, there are no major differences from the ES44DC.