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EMD 567 Prime Movers

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  • Member since
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EMD 567 Prime Movers
Posted by hobo9941 on Tuesday, May 01, 2018 10:38 PM

Did all EMD units, GPs, Fs and Es make transition? I have several early Soundtrax decoders for EMD 567s that make transition and sound like the real thing. That said, some of the newer DCC sound decoders for EMD 567 do not make transition, but simply rev up the prime mover sound for each notch. Is this correct. I have listened to some sound samples from a couple decoders and they just rev higher and higher with no transition. Did the E units with dual 567s make transition? Thanks.

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  • From: Collinwood, Ohio, USA
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Posted by gmpullman on Tuesday, May 01, 2018 11:16 PM

They all had a transition. The earlier FTs and F3s the transition was performed manually by the engineman, based on load meter and speed recorder indications. Same with Es before the E8. I believe all the GP7s were automatic transition both up speed and down. There may have been a few later E7s built with automatic.

The throttle had to be set to a lower notch (either below 3 or even to idle? I don't recall but I'll have to check) in order to prevent flashover, or arcing at the motor commutator during transition. As the train and engine speed reduced, transition would also have to be stepped down as the speed dictated. There was a carry-over period when some EMDs had automatic forward transition but manual backward transition.

Transition became automatic, based on generator load and engine speed after the F3 and E7. I believe there was a manual overide and if you had an early EMD in the consist the engineman had to manually set the transition. Many roads later upgraded the older units to automatic transition.

After the GP- SD-35 a different method of motor control allowed the traction motors to be all wired in parallel and the relay transition was eliminated. The 35s had a sixteen-step transition using various field shunts.

One of the great features of the Loksound Full Throttle upgrade is that I can simulate transition while bringing my train up to speed. Brings back a lot of memories riding behind three or four E-units and hearing all those pistons "changing gears" as we gained speed!

Regards, Ed

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Posted by hobo9941 on Wednesday, May 02, 2018 10:34 PM

Thanks for that detailed answer. I was listening to some Loksound samples for an E-7 I recently purchased and they did not have any transition in the sound samples. It said "no transition" on the sound sample. That is what prompted my question.

Here is the Loksound sample for the E-7. Give a listen and see what you think.

http://projects.esu.eu/projectoverviews/2

  • Member since
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  • From: Collinwood, Ohio, USA
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Posted by gmpullman on Wednesday, May 02, 2018 11:39 PM

Hi,

The link sends me to the general Loksound download page.

The Amtrak E8 apparently uses the earlier 567 engines (file xxx61) and the Erie (file xxx83) the later 567C.

I like the xxx61 file better, just to my ears anyway. Seems like ESU should switch the photos with the Erie engine on the older prime mover and the Amtrak on the later one.

I didn't find anything in the notes about no transition. I think all the sound decoders have a method of back EMF "loading" like Soundtrax DDE, BLI "Sound Of Power" and "Auto Notching" on the WOWsound.

These aren't exactly transition, of course.

Like the "Drive-Hold" feature, it is fun to play with and I like to demonstrate it to visitors but after I have five or six trains running I really don't have time to mess around with all those "bells and whistles" and the associated button pushing.

As I said in my first reply, it is fun to bring a train up to speed, using drive hold to up the RPM while the train is still slugging along at fifteen or twenty. Then once up to track speed I can lower the engines RPM to around Run 2- or 3 then slowly bring the RPM back up a little. To me, this simulates transition very nicely.

Cheers! Ed

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Posted by Overmod on Thursday, May 17, 2018 3:00 AM

gmpullman
Transition became automatic, based on generator load and engine speed after the F3 and E7. I believe there was a manual overide and if you had an early EMD in the consist the engineman had to manually set the transition. Many roads later upgraded the older units to automatic transition.

As mentioned before in other posts, the PRR passenger E8s did not have automatic back transition and this caused some major flashover issues -- as I recall, at the main generators and not the motors -- when those engines came into use in TrucTrain service in the mid-Fifties, when freight engineers expecting automatic back transition as on typical freight power closed their throttles a bit too quickly at high speed.  It would be interesting to develop algorithms to mimick the 'correct' throttling-back behavior, and sound, when operating in DCC, and this might add the capability to do speed-sensitive control of engine sound clips to produce true 'transition' effects proportional to speed and perceived load.

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  • From: OH
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Posted by BRAKIE on Friday, May 18, 2018 3:51 PM

Here's another wrench in the works. EMD's 567 series had a slightly different sound.

EMD SW series had a "chant" like sound while idling.

Larry

SSRy

Conductor

“Shut one’s eyes tight or open one’s arms wide, either way, one’s a fool.” Flemeth-the witch of the Wilds.
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Posted by BigDaddy on Friday, May 18, 2018 5:19 PM

BRAKIE
EMD SW series had a "chant" like sound while idling.

Brother Lion to the white courtesy phone

 

Henry

COB Potomac & Northern

By the Chesapeake Bay

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Posted by Eric White on Thursday, May 24, 2018 10:14 AM

I think the EMDs sounded more like this:

 

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Posted by rrinker on Thursday, May 24, 2018 6:36 PM

"I'm not dead yet"

"Well, you soon will be"

Much as I love Alcos, that probably applies more to them than to EMDs

                                  --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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  • From: Northern Virginia
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Posted by riogrande5761 on Friday, May 25, 2018 8:11 AM

And thus the topic of prime movers has gone south, from chants, to gregorian chants to bring out your dead, Monty Python.  Gotta love MR forums!  Dunce

Rio Grande.  The Action Road

Silly Aspie's, I have NT syndrome

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