the size of the beasts!

And when that SD35 first came out (the prototype) it was state-of-the-art.

Rick

And the SW9's are even smaller .  Modern power is at least (2) if not (3) units from the 1950's or 60's.    More Power Tim  

 I used to wonder about why the porches on the SD40-2s were so long. I really didn't think that much about traction. Comparing some models I have, I'm wondering if the older GE's stuck to the rails better in their day?

Wow,  I thought the thread title said, "The size of the breasts" 

Too early in the morning, need coffee.

Larry

One of my favorites is this photo when my Sunset 44-tonner arrived. Early GE vs. Late GE.

 Wow Matt.

I'd have to put sound and control into that little bugger. Great find!

Sure gives a reference to how small it is.

I always wondered when I saw long trains pulled by just one modern engine. Looking at how much longer it is than that switcher, it makes better sense to me.

 I just was shocked at how short a SD35 was. I figured it was closer in length (to the modern ones) than it really is.

The SD35s were fairly short for six axle units.  But the SD45 of just a couple of years later was much longer and 1100 horsepower more powerful.  All those extra horses were thirsty and much of the greater length was devoted to a larger fuel tank.

Or, to put it another way line up 10,000 HP worth of SD35s.  You will have 4 of them.

Line up 10,800 HP worth of SD45s.  You will have three, but about the same total length compared to the four SD35s.

SD35s, 40s, 45s and modern GEs and EMDs can all be ballasted to meet a railroads needs for adhesion and axle load limits.

Thanks Ted!

I have been reading about it lately too.

It is interesting to read the history of GE and EMD. Both developed these beasts into what we now see.

 I never studied much of the U boat era GE's other than looking at pictures.

Sometimes it seems that it's easier to find stuff to read about EMD's history.

Prior to the introduction of the "Dash 2" model line, EMD Engineer & manufacturing moved to standardize the underframes for the SD38/SD40 and the SD45/F45/FP45 models. Thus, the 38/40 series units wound up with "front & back porches" since this models had the shorter 16 cylinder power plant, while the 45 series units had the longer 20 cylinder power plant.

Hot water. Is that why the SD40 is shorter in length then the Dash 2?

I hope you find some kind of humor in my posts. I always get a kick out of yours'!

I was just "thinking" that this GE U boat in the pic of mine, looks longer for it's era. I didn't get specific info or look at their whole line-up. I don't even know the years it was produced. I always think of it as an old diesel.

 That U33 is about the same length as the SD50 in the pic. Maybe EMD stuck with that standardized frame length into the SD50?

 I need to read some more! Info doesn't stick with me.....

No, because with the introduction of the "Dash 2" line, one of the biggest improvements was also the introduction of the HT-C three axle truck. Unlike the previous "SD Truck", which had to have the third traction motor mounted in reverse, the new design HT-C truck had an end transom to support the third traction motor, thus making the HT-C truck much longer. The HT-C truck also had a much larger diameter center bearing for increased torque transmittal to the underframe.

The HT-C trucks being longer, necessitated a longer underframe, for all the various "Dash 2" models.  

 "from a performance perspective one of the most important attributes of the SD40-2 was the introduction of EMD's new HT-C truck."

" the continuous adhesion factor was boosted from 18 % on the sd40 to 21% on the SD40-2. In ideal conditions the sd40-2 is given 27%.

 ....."is just more than 3 feet longer than the sd40 ..."

 ...".it rapidly became the standard locomotive of the 70s and 80s"

(Brian Solomon- Modern Locomotives)

Thank you Hotwater

I will probably put a DCC sound decoder in it at some point.

The SD35 was a surprisingly small locomotive, and at 60 feet was only about four feet longer than the GP35 as I recall. Interestingly enough, the GP38-2 is only about a foot shorter than an SD35. The longest single-engine EMD I can think of is the SD90/SD9043MAC at around 80 feet. Adds new meaning to "go big or go home". The DD35/DD40 engines were actually two GP35/GP40's in a single package.

Yes, these are big, impressive, powerful locomotives, but, here's something to contemplate: at a base (unballasted?) weight of 408,000 pounds for an SD70ACe, it is only slightly heavier then a Canadian National 4-8-4 at 400,000 pounds. But a heck of a lot more tractive effort and horsepower. A CNR 4-8-4 is amoung the smallest of the 4-8-4's!

 To be honest, I don't understand how the weight is spread out on a steamer's axles. For example: The trailing truck is to help support the weight of the firebox? Is there some type of suspension on the trucks?

How much of the total weight does the main drivers see?

 Might sound stupid, but I just don't know? I don't see any springs on the lead trucks for suspension, so I can only guess they just are for guiding the thing around turns??

 With the weight of these big diesels spread out over the boogie's axles, and each axle with slip monitoring, I imagine they out perform there predecessors quite well.

 I'll have to look up what's the tractive effort of a SD40-2 vs a modern one.

My experience with GE Locomotives both older and new or modern day is most on dry rail are fantastic pulling engines. You could get into the short time high amperage load and keep the train moving without having to lay down sand on the rail. Wet or ice on the rail a totally different story.

The GEs were prone to slip when in a high amperage pull even with the sand on. This would allow a run-in of slack in your train and when the slack worked it way back out you usually broke a knuckle or drawbar within the head 1/3 of your train. On the newer GEs sanding was computer controlled according to the wheel slip senor until you got below 13 MPH where the Engineer had manual control. The GEs were slow to load and you could not re-cover quick enough to prevent this from happening.

Was it Clint Eastwood who said," A man's got to know his limitations"? A good engineer had to know his engines. 

Joe,

I'm sure HW can do a great job of describing HOW the weight is loaded on the Lead truck, drivers and trailing truck on a stem locomotive.  As to an example of weight, a UP FEF-3 had 100,600 lbs on the leading truck, 270,300 lbs on the drivers and 119. 800 on the trailing truck.  Thus, the FEF-3 has almost as much weight per driver axle as Mark mentioned the SD70Ace has.

ChipR

Is there some type of suspension on the trucks?

Joe

If you are going to travel at 9 mph, let alone 90 mph you are going to need a sprung suspension.  If you visit the Pennsylvania State Railroad Museum you can walk under a PRR 2-8-0 and have a look.

How much of the total weight does the main drivers see?

Figures for most steam locomotives are available on line.  Here are the numbers for the UP FEF-1, 2 and 3.

For more see http://www.steamlocomotive.com/northern/?page=up

The Timkem locomotive (coming soon from 3rd Rail : )  was designed to run on railroads with different axle load limitations.  The suspension systems for the lead and trailing trucks could be adjusted to take weight from the drivers on roads with lower axle load limitations.  On lines with higher axle load limits weight could be taken off of the lead and trailing trucks and carried by the drivers for better adhesion.

Thanks all for the info.

The laugh that I always have is when the FM 2400 HP trainmasters are described as "monsters". I guess that they were when compared with a 1750 HP F7. But the latest models from the two major builders are truly monsters, both dimensionally and in performance. Starting tractive effort for each is close to 200,000 lb, and the weights are in the 412-432,000 lb range. That rated starting tractive effort is twice what a Challenger mallet can muster.  A single unit will handily outperform almost any steam mallet in the low speed range. It is what is required when the old 40 ton box cars have been superseded by some hoppers that weigh 268,000 lb loaded.

"These porches differentiated the SD40-2 from its earlier cousin, the SD35 and were the result of the SD40-2's requirement for a longer frame, which helped increase the locomotive's tractive effort."

Engineer Joe,

Your behemoth CSX locomotive, in the foreground, is so large it seems to be of a 'G' scale size!

Ralph