Well, switching with 6-axle units is not often done, but back in the early 90s, the SP Magma Turn local would sometimes run SD45s or SD40-2s - once even a GE C40-8. Normally the alloted power was an MK rebuilt GP40-2. The 645 engine is still very much alive and EMD continues to build it. As for the 567 - if you have a "C" or "D" crankcase, you can replace the power assemblies with 645 power assemblies and have a "645C" or a "645D".
A lot of GP40 class engines have had their turbos removed and replaced with Roots blowers, making 'de-facto' GP38 class engines (GP38-2 or GP38-3). BNSF recently acquired some old GP35 hardware that had power assemblies replaced with 645 parts and deturbo-ed, these are considered "GP38-3s" as well.
These engines will continue to run, it wouldn't surprise me to see a GP7 doing yardwork 30 years from now. By then, these units will be 80+ years old! Remember, there is a large aftermarket for EMD powerplants - even General Electric rebuilds EMD units and offers EMD replacement parts including power assemblies.
We switch with SD40-2s all the time in Janesville. In Horicon, it has been done, but the curves in the car shop area are pretty tight for such a big motor. There, a GP7 with working switch mode does pretty good. Our best running GP38s are the ones that are deturbo'd GP40s. Maybe because they are heavier.
The GP20D uses a Caterpillar engine.
Alcos and FMs are still made as well, they are popular in marine applications.
Mike WSOR engineer | HO scale since 1988 | Visit our club www.WCGandyDancers.com
I was just wondering. That "helicopter" sound of "untuned" injectors that was mentioned earlier. How come it doesn't happen as often on read vehicles, like trucks. Is it something about the GE and EMD engines that make them more vunrable to this issue?
snagletooth wrote: I really need to start another thread, but don't know how. It seem's to me the 40 series and even the 50 series are worn out and probbly not up to their full horsepower (justy an opinion, and I know what an opinion is worth), but an SD70 on an grain elevater in 2030 is just unrealistic. I'm not talking about now, I'm asking about 20-30-40 years from now. if i should start another thread, please let me know how , I think this is worth a nother disscusion. But to getg back to the original topic, YES, I DO NOTICE A "SLIGHT" DIFFERENCE BETWEEN A 567 AND A 645. VERY SLIGHT!!!
A locomotive doesn't "wear out" like a car. A 30 year old SD40-2 in line haul service has probably been through a half dozen engine overhauls (about half of them just power assemblies) and a dozen or so injector change-outs. Even at the wear limit, the diesel engine will still make rated HP and fuel efficiency. The easiest way you can tell that an EMD engine is healthy is to look at the stack after it's been running notch 8 for 5 or ten minutes. If it's clear, then the engine is healty. If there is any trace of black, then somethings not quite right.
You can keep any locomotive going indefinitely as long as you can get parts for it. What causes you to replace one model with another is strictly economics. It's hard to justify replacing a GP38-2 or SD40-2 in yard or local service because they are so cheap to keep. As long as you don't run into EPA regs or use them in a service that burns a lot of fuel, there's no reason these models won't be around for another 50 years.
An SD50 is such a complicated nightmare electronically and the F3 engine is such a pain, that it'll probably be cheaper to keep SD40-2s for yard & local service than modify SD50s. SD70s with radial trucks might just find a long life on twisty coal branches and in mountainous pusher service. It would be hard to use them in yard and local service because of their cab.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
I've slowed down the recording of that chugging engine, and here is what I was able to hear
there is a repeating period of 8 beats, and one of those beats is so loud that it makes the whole engine sound like it's the only cylinder that's firing.
It goes like this
1 2 3 4 5 6 7 8
the big 5 is the sound you hear at normal speed of the sound file.
It's so dominant that you can't even hear the other beats unless you show down the recording and increase volume in an editing program.
I guess this proves what Don was saying. This can only be a dominant engine.
But I think the alternate explanation is a hole on the exhaust manifold of one of the cylinders
Now that I think about it. I've heard some buses that sounded like that. But that was a manifold rapture, at least I think it was. Could be the same injector misadjustment though as on these locomotives.
By the way, how do you call such a phenomenon? I tried googling for "dominant cylinder" or similar phrases but found little results. There must be a common technical term for such a thing
Normal aspiration exhaust versus turbocharged aspiration exhaust on any diesel prime mover makes all the difference. I never though I'd miss the sound of a hard working EMD 645, but that I do miss 'em nowadays means I've become a greybeard for sure. As for missing the wonderful "chant" [thanks to the late Trains mag editor David P. Morgan for that perfect descriptive] - I can't begin to say how much I miss that distinctive EMD first generation sound. I also miss the fantastically whacky syncopations of Baldwin diesels (with their de La Vergne prime movers) and even earlier GE U-boats... Yup, I'm a greybeard!
The difference in sound of 567 roots blown engines versus roots blown 645's may be explained by the difference in the exhaust manifold design. Once the 567 engine had a top deck like current 567-645-710 engines instead of the prior U-deck as it was called IIRC, the 567 engines got what were called at EMD Vee leg manifolds. The manifold chamber is a 15" round cylinder and the Vee leg manifolds had connecting pipes to the top deck flange, where they bolted over the exhaust outlets, that connected tangentially to the barrel of the manifold. So as a cylinder fired, its mate accross the engine that fired 45 degrees of crank rotation later caused an opposing swirl in the manifold chamber. On GP's and SD's with 8 or 16 cylinders, the manifolds were made in assemblies that covered four cylinders, two opposing pairs in the engine. Two manifolds were joined by an 10" diameter tube with a band clamp to seal it. Only one of the pair of manifolds connected together had an exhaust stack, the typical oval shape about 4" by 12". The location of the stack depended on the dynamic brake arrangement, whether none, GP or SD. On the SD with Dyn Brk, the stacks were at the very ends of the engine. When an non-DB and on GP's, the stacks were over the cylinder pairs one in from each end of the engine.
When the 645 was introduced, the manifold legs were made parallel so they wouldn't created the opposing tangential flow, otherwise they were the same. This applies to the standard manifolds, which were non-spark arresting.
Only a few customers, most notably the MoPac, got non-spark arresting manifolds. But MoPac got a special arrangement on their GP38-2's that had 4 stacks, one on each manifold, but two manifolds were still interconnected with the band clamp tube arrangement. MoPac developed their own spark arrester which was a screen box that they mounted on the loco roof, one over each stack outlet.
Most customers of 645 engines got spark arresting manifolds that differed still in design. These manifolds had a special leg arranged so both cylinders opposite each other caused a tangential flow in the manifold in the same direction. These manifolds had a spark trap that captured by centrifugal action carbon particles that otherwise would exit the stack and possibly set wayside fires. The US Forest Service has a performance test for spark arresting devices that must be met to operate thru national forests. The bottom line is that all the class 1 railroads applied spark arresters of the EMD design or competitors designs such as the Heaton spark arrester used by MoPac or spark arrester manifolds made by the Farr Co. or others.
Most switchers used 8 or 12 cylinder engines. The 8 cylinder arrangements were just half of a 16 cylinder set but with the stack changed to a tapered round instead of the straight oval. 12 cylinder engines got special manfolds that covered 6 cylinders each with no interconnecting between manifolds and round tapered stacks. Silencing manifolds were basic on switchers and spark arresting were optional.
When the 1980 noise regulations for locomotives went into effect, EMD released a new set of manifold designs that differed significantly in that they were both silencers and spark arresters in piggyback chamber arrangement covering 6 cylinders in each. On 16 cylinder engines there was a small manifold covering the middle 4 cylinders with pipe connections at either end to the larger manifolds. All had round, straight stacks. Swithers used the same manifolds as GP's and the result was a raised portion on the hood that covered the taller manifolds.
E units used an entirely different arrangement where all 12 cylinders were connected in line and exited the end of the manifold at the governor end of the engine into a 90 deg elbow with a pipe thru the loco roof so there was just one stack per engine.
My point in all this is that it would be amazing if they all sounded exactly the same since there are a range of manifold types that have a huge effect on the sound created when all cylinders are coupled into them. Some were silencing types, some not; the Vee leg are different than the straight leg. The retrofit of most locos with spark arresters from numerous companies has a huge effect.
This discussion completely ignores the changes that were going on in the engine that effect the sound produced. Fire ring pistons, injection timing and duration, peak pressure, cam design changes, etc.
I was the sound engineer at EMD during the 70's. I designed the spark arresting-silencing manifolds that became standard in 1980. I was resposible for all locomotive sound measurement. There was nothing louder or harsher than the MoPac 4 stack arrangement I can assure you.
Dave
bogie_engineer wrote: There was nothing louder or harsher than the MoPac 4 stack arrangement I can assure you.Dave
There was nothing louder or harsher than the MoPac 4 stack arrangement I can assure you.
I can back that up. I have seen them running in high throttle powering locals around Fort Worth, TX and they have to be the loudest EMDs I have heard.
neil300 wrote: bogie_engineer wrote:There was nothing louder or harsher than the MoPac 4 stack arrangement I can assure you.DaveI can back that up. I have seen them running in high throttle powering locals around Fort Worth, TX and they have to be the loudest EMDs I have heard.
bogie_engineer wrote:There was nothing louder or harsher than the MoPac 4 stack arrangement I can assure you.Dave
I third it, I can remember seeing and hearing the ex-MoPac GP35ms the Wisconsin Central had. Some crews nicknamed them Harley-Davidsons (and everyone knows what Harleys sound like!!!)
Randy Vos
"Ever have one of those days where you couldn't hit the ground with your hat??" - Waylon Jennings
"May the Lord take a liking to you and blow you up, real good" - SCTV
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