How Many Notches (vs notching sound)

[melarson]

I have the EMD 567 prime mover loaded for my E8s and have set them for manual notching.  From idle there are only seven changes in the sound as it revs up through the notches.  Shouldn't there be an eighth level (corresponding to eight notches)?  Are other prime mover sound files the same or is the 567 just an anomaly?  I'm curious as to how many notches other PM sound files have.

[William Brillinger]

I believe notch 1 is idle. That is to say, there is no notch zero.

[melarson]

OK, thanks Bill.  For whatever reason I always thought there was a separate idle, and then notches 1 through 8.  I will also ask a retired BNSF engineer friend of mine when next I see him.  I'm curious as to how the prototype worked.  Not that it will impact how the RailPro sounds will work.  That said, please don't misunderstand; I couldn't be happier with the system!  In your thread "Getting the word out" Alan suggested upgrading the description of RP (in part: "RailPro is a powerful full featured control system that is amazingly simple to use.").  And I agree 100%.  In addition I'll offer this (adapted from Model Railroader magazine's no-longer-used slogan): "RailPro. Model Railroading is Fun, Again!"

[William Brillinger]

I'll check with my engineer friend also.  It's a good question!

[Alan]

Straight from the guys that originally designed the 567....



A great read: http://utahrails.net/pdf/EMD_567_History_and_Development_1951.pdf

[KPack]

As stated, notch 1= idle and first power notch.  There is a low idle on some prototypes but I couldn't tell you what locomotives utilize this feature.  I believe that low idle is really only utilized when the locomotive is sitting for long periods of time (i.e. train tied down overnight and engine is kept running to keep the brakes charged).  For our purposes only the normal 8 notches are really useful.  A low idle might be something to be added to Railpro later, but the likelihood of it ever really being used as we operate is pretty slim.  At least for me it would be.

-Kevin

[William Brillinger]

From an SD40 Manual posted online:

Throttle Lever

The throttle lever actuates switches within the controller to establish low voltage electrical circuits to the rn engine governor for purposes of controlling engine speed. The throttle has ten positions namely, STOP, IDLE and running speeds 1 through 8 as shown in Fig. 2-6. Each of these positions is shown in the illuminated indicator in the upper left hand corner of the controller.

To stop all engines, the throttle lever is pulled out away from the controller and then moved one step beyond IDLE to the STOP position. The IDLE position is as far forward as the throttle lever can be moved without pulling it away from the controller.

Each running notch on the throttle increases locomotive power by increasing generator excitation or engine speed or both. At time of locomotive start each notch provides a fixed and immediate level of generator excitation. This level brings about an immediate and fixed response to throttle position during starting.

When operating in dynamic braking (selector lever in "B") the throttle lever serves as a braking handle. It moves freely without notching to control dynamic braking.

from: http://www.kirara.co.uk/info/SD40%20-%20Operator's%20Manual/

[William Brillinger]

Tom says the description in that manual is wrong. He will take a video tonight at work of how it works.

[G8B4Life]

It will be interesting to see this video Bill. I was never a driver but have been in cabs a few times and I remember 8 power notches.

What I have read (from info on LokSound) and thinking about it I can pretty well confirm what was written, is that the prime mover RPM in notch one is actually lower than in idle as the prime mover loads with the generator. It's really noticeable with one of our loco's that had 6-567 and 6-645 engines fitted.

This might explain why the RailPro file, and all the LokSound files I tested only had 7 notches.

Tim...

[William Brillinger]

NOTE: I split this topic because it's not really part of the "Notching across a consist" discussion.

[William Brillinger]

Here's what I anticipate seeing in the video:

We know the Throttle is controlling the electrical connections for the traction motors, not the rev's of the Prime Mover.

The throttle moves side to side to advance the notches.
The throttle moves up and down to engage or disengage the electrical circuit.

So I expect to see 1, 2, 3, 4, 5, 6, 7, 8  left to right positions for the throttle and DOWN is "OFF" electrically, which is "IDLE" for the Prime Mover.   

So going from OFF to 1 does not change the governed rpms of the prime mover but will bog the prime mover down as it is loaded until it returns to the proper RPM. Which lines up with what Tim suggested about notch 1 being "lower" than Idle.

Here is a great thread on MRH that is very related to this discussion:
http://model-railroad-hobbyist.com/node/24130

[G8B4Life]

I think you might be right there Bill, bogged down not lower RPM, though the document I read did say lower.

I did find a video that demonstrates this bogging down with one of those 6-567 prime movers. It's noticeable at about 1:17 and quite noticeable at about 2:40, both when starting off.

Maybe this bogging down is not distinguishable enough for most loco's to be included in sound files so they make idle and notch 1 the same.

As for the up and down movement of the throttle well I can't say I've ever seen that. Different control stands perhaps?

- Tim

[William Brillinger]

Well my memory from my teenage years riding along on GP38-2's and 40-2's is all wrong.  My memory told me there was an up/dn lock & ratchet kind of system on the throttle.

so....   Here's the video. This is a GP38-2.

Video courtesy of Tom G.

There is an idle position plus 8 "notches" and you'll notice that idle and 1 are identical. If the reverser was not in neutral, the prime mover would have bogged down a bit in notch 1.

Cheers!

[KPack]

Nice video Bill.  Thanks to Tom for providing that.  So it looks like we were on the right track then....8 notches and notch 1 = idle.

As a side note, I would love to get a good recording of that GP38-2.  A really good 645 roots recording would be welcome indeed.

-Kevin

[melarson]

Thanks to all who contributed to this thread.  I now have a better understanding how the prototype operates and can use that knowledge to more accurately operate my models.  And I can dismiss the thought that the sound files need to be changed, because they don't.  Many thanks again.