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diesel notch power settings

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Posted by timz on Tuesday, August 25, 2020 10:37 AM

That reminds me of another question --

When a current GE is in Run 8, the engine isn't always at maximum RPM? At low locomotive speed, prime mover RPMs might drop while the locomotive continues to produce maximum TE in Run 8?

Did/do FDL16-powered units do that?

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Posted by Overmod on Tuesday, August 25, 2020 10:52 AM

timz
When a current GE is in Run 8, the engine isn't always at maximum RPM? At low locomotive speed, prime mover RPMs might drop while the locomotive continues to produce maximum TE in Run 8?

That is a good question.  In the days before FADEC EFI the governed maximum speed is what would be commanded in Run 8 (with the governor of course apportioning fuel to keep the engine at that rpm regardless of load).  It would make sense for a computer to drop the rpm as noted for physical deloading, both for the significant aggregate fuel saving and reduction of wear and tear. 

I suggest that the immediate path to a practical answer involves a BatLight call to Randy Stahl...

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Posted by BigJim on Tuesday, August 25, 2020 6:10 PM

Overmod

 

 
timz
When a current GE is in Run 8, the engine isn't always at maximum RPM? At low locomotive speed, prime mover RPMs might drop while the locomotive continues to produce maximum TE in Run 8?

 

That is a good question.  In the days before FADEC EFI the governed maximum speed is what would be commanded in Run 8 (with the governor of course apportioning fuel to keep the engine at that rpm regardless of load).  It would make sense for a computer to drop the rpm as noted for physical deloading, both for the significant aggregate fuel saving and reduction of wear and tear. 

 

I suggest that the immediate path to a practical answer involves a BatLight call to Randy Stahl...

 

When operating in notch 8 for extended periods of time and additional traction motor cooling is needed, GE units will increase rpm to 1050, with no increase in HP.

And yes, if a GE loco is in the lead with an EMD trailing, under the right circumstances, when the throttle is increased the EMD will bump the GE telling it to quit picking its nose and start loading!!!

.

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Posted by oltmannd on Tuesday, August 25, 2020 9:23 PM

timz
Until dunno-when, GEs had 16-notch throttles -- the engine speed increased at alternate notches, with just an excitation increase in the in-between notches.

By the time the U25s with their half notches got to Conrail, all of that nonsense had been removed but the throttle still moved in half notch increments.  There were still engineers who had all sorts of theories on how to use the half notches, even though they didn't work anymore!

timz
In the 1970s, GE (trying to save fuel) tried running with three (?) engine speeds instead of eight -- the engine was at 1050 RPM in notches 6, 7 and 8, or some such thing.

The 1-5-8 speed schedule. Trying to get the darned things to load a bit quicker. Notch 5 engine speed in notches 2-5, Notch 8 after that.  A good chunk of PC U23Bs had this silliness.  It was superceded with "skip 3, double 6".

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by Paul Milenkovic on Wednesday, August 26, 2020 3:06 PM

oltmannd

 

By the time the U25s with their half notches got to Conrail, all of that nonsense had been removed but the throttle still moved in half notch increments.  There were still engineers who had all sorts of theories on how to use the half notches, even though they didn't work anymore!

 

 

Is this anything like those placebo walk light buttons that apparently have not effect on the scheduling of the cross walk light?

If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
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Posted by Overmod on Wednesday, August 26, 2020 5:33 PM

Paul Milenkovic
Is this anything like those placebo walk light buttons that apparently have not effect on the scheduling of the cross walk light?

Only if the buttons were originally working but were then quietly disconnected as being an annoyance to vehicle operations...

Remember that these would result in weird loading mismatch with ordinary 8-notch units if more aggressive excitation is what the half-notches control and the engineer isn't careful to count if he is engaging a half or whole notch in a one-notch throttle lever transition.  If I remember correctly the engine speed changes were artificially dashpotted to avoid smoke shows due to turbo lag, and the purely loading transitions of the intermediate notches might not have had a comparable long 'time constant' -- as a feature, of course.

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Posted by oltmannd on Thursday, August 27, 2020 8:24 AM

Overmod
.  If I remember correctly the engine speed changes were artificially dashpotted to avoid smoke shows due to turbo lag, and the purely loading transitions of the intermediate notches might not have had a comparable long 'time constant' -- as a feature, of course.

The speed changes were fast.  The loading was slow.  If you wipe the throttle on a GE Dash 7 or 8, it's 80 seconds to full load, and more than half of it occurs in the last 20 seconds.  

 

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by zugmann on Thursday, August 27, 2020 10:54 AM

oltmannd
The speed changes were fast.  The loading was slow.  If you wipe the throttle on a GE Dash 7 or 8, it's 80 seconds to full load, and more than half of it occurs in the last 20 seconds.  

"Train handling exception: throttle modulation."  

[acknowledge]

   The opinions expressed here represent my own and not those of my employer or any other railroad, company, or person.

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Posted by oltmannd on Thursday, August 27, 2020 2:36 PM

zugmann

 

 
oltmannd
The speed changes were fast.  The loading was slow.  If you wipe the throttle on a GE Dash 7 or 8, it's 80 seconds to full load, and more than half of it occurs in the last 20 seconds.  

 

"Train handling exception: throttle modulation."  

[acknowledge]

 

If you have a train all stretched out and you are in a position where you can't possibly generate enough TE to get a knuckle...wiping the throttle will just get you where you're going faster

An EMD (pre-AC) - wiping the throttle would get you to full load inside of  25 seconds, nearly linearly.

GE CHEC had "three slope curve". 

God bless you if you had to start a train on the grade with a B36 leading and GP40s trailing...and you needed all three to get rolling.

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by zugmann on Thursday, August 27, 2020 2:58 PM

oltmannd
If you have a train all stretched out and you are in a position where you can't possibly generate enough TE to get a knuckle...wiping the throttle will just get you where you're going faster

Not according to the tattle-tales that live in teh magic PTC box. 

   The opinions expressed here represent my own and not those of my employer or any other railroad, company, or person.

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Posted by oltmannd on Thursday, August 27, 2020 3:11 PM

zugmann

 

 
oltmannd
If you have a train all stretched out and you are in a position where you can't possibly generate enough TE to get a knuckle...wiping the throttle will just get you where you're going faster

 

Not according to the tattle-tales that live in teh magic PTC box. 

 

okay.  They'll just get you to your trial faster.

Do you get summarily shot for stretch braking?

 

-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

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Posted by zugmann on Thursday, August 27, 2020 3:23 PM

oltmannd
Do you get summarily shot for stretch braking?

Oh yeah.. it's like a game of BINGO. All sorts of stuff they tell you they don't like.

It's a whole new railroad.  

 

   The opinions expressed here represent my own and not those of my employer or any other railroad, company, or person.

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Posted by jeffhergert on Thursday, August 27, 2020 3:50 PM

For us, they only consider it stretch/power braking if you release the air above a certain notch.  I think they raised it back to notch 5, it was notch 3 before.  It's one of those items they like to change every so often, as the mood strikes them.

The managers always want to see "stair steps" on the tapes as one opens or closes the throttle.  One coworker was telling me his manager was riding with him.  He went to engage one of the energy management systems, which once you push the button you move the throttle to notch 8.  It doesn't engage until the thottle is in 8 and moving the throttle doesn't register anything.  The computer holds it in whatever position it was in until fully engaged.  So you can just move the throttle to 8.  So my coworker just swiped the throttle to 8.  His manager asked him, "WHAT DID YOU JUST DO!"  The MOP started reading him the riot act when my coworker informed him about initiating EMS. 

Now, the last time this manager worked as an engineer was before EMS and PTC.  You would still think he would be up on how things work.

Jeff 

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