Large Scale Central

Does the gearing really not matter?

General Discussion
#61
Greg Elmassian said:
SNIP Add to this one final small point... your greatest traction is JUST BEFORE the wheels break loose and slip... (difference between static and kinetic friction for you physics guys) so you want to get all the "smooth power" up until that point in your loco to maximize pulling power. This seems to speak of lower gear ratios and smoother power transistions, not a BEMF circuit trying to compensate load and power at EVERY commutator segment.

I am a DCC guy, and I have BEMF decoders. I follow the old adage: make your loco run as well as possible on straight DC, electronics cannot turn a poor running loco into a great one.

Regards, Greg


Thank you Greg.

Because “they” can “accomodate” crappy drives by playing with electronics “they” do.

Plus, it also helps cover up “their” mistakes. Add a bit of spin and a lot of BS and you have the perfect Stanley Ames argument.

Tha Bachmann K-27 gearbox is brilliantly made. Very high quality.
In fact, it wouldn’t be able to perform very well at all with any less of a quality build.
Just a pity it has the wrong ratios.

#62

Tony…I’d go a little further…if indeed it is an incorrect ratio, then the real pity lies in the fact that the maker is unwilling to fess up.

#63
Tim Brien said:
Zubi, a very thorough response, which in my mind proves just one thing - a layman with little direct knowledge, but a lot of experience, is as knowledgable in a particular situation as a college professor.
Tim. I generally agree, although experience alone does not help to understand, explain or quantify the problem. Still, I generally agree with your statement and this is why I was so surprised to see that people who jumped on Mr Ames here do not seem even to understand his statement cited in the opening of this thread.
Tim Brien said:
I know my basic laws, but I also know what I want from a model. Certainly, the assumption is that the higher gear ratio on the production 'K' is able to use the power of the Pittman motor, but at what cost? You mention the noise of a motor at maximum rpm as a criticism and yet, most operators would never attain maximum rpm, whatever gear ratio was used.
Tim, this is plainly incorrect as a general statement and I am sure that you realise this. If you used twice 1:29 that is 1:58 ratio you would have a configuration capable of an even higher tractive effort, 58.4kg to be precise, but you would need to operate at 6150rpm, which requires 19V, to achieve the speed of just 12.6mph (20.3km/h). Of course you can do this, but the point of this thread is that it is useless to have such a high torque on the drivers when the locomotive weighs some 5kg!!! This is exactly the point Mr Ames is making in the posting referenced here and it is perfecty correct.
Tim Brien said:
The 'opponents' of the Stanley Ames camp are not boggle-eyed youngsters, bent on wringing every last drop of speed out of their locomotive, but experienced model railroaders, who want a scale model to behave as a scale model. I am not criticising Stanley (or yourself), but in his defense, he is more interested with attaining the prototypical top speed of the loco, at 18 volts and baffling us with electronics than with providing us with a locomotive that performs as brilliantly as it looks. Many do not use 18 volts as their operating voltage, so how valid is attaining a maximum speed if the fixed input criteria is actually a variable?
Hmm, I do not believe anyone unless they (or I myself) can prove what they say. You can throw away the electronics and verify how the motor performs on your K. You say 18V, LGB locomotives are all designed to run on a much smaller voltage range at the motor before reaching unprototypical speeds and yet I have never heard of anyone claiming they are underpowered or overheat, and they use electronics too, also severely to reduce the voltage range on digital sound versions to allow standby sounds+light. Generally, electric locomotives are grossly overpowered compared with the prototype - yet noone seems to mind this "inaccuracy" with respect to prototypes;-))) Once again, if we move to the more general discussion of the optimality of the 1:14.5 gear ratio chosen I would need to see some proofs in a form of calculations or properly set up experiments to believe that it is sub-optimal in any respect other than the prototypical inaccuracy of the speed achieved at say 12V and above. Best wishes from Tokyo, Zubi
#64

Zubi.
They don’t overheat because they have a fan on them.
They do draw more current than they should.
That has been tested and proven.
Mr Ames was testing tractive effort on brass or possibly SS rails. Our tests have been on filthy dirty mostly aluminium track which results in a lot more grip by the drivers. This equals more hauling power which requires more energy be burned which can overheat an ESC and flatten the batteries faster than it should, if the gearbox ratios were as originally specified and not half.

#65

Just speaking my mind guys, as puny as it feels today.

Cale, have read and heard and believed that phrase for many years, even back into the 60’s when “pulse power” (half wave AC) was going to solve everything. Kind of goes along with “you never get something for nothing”.

Tony, I worked for a little company called Hewlett Packard, and we used to make XY plotters with nice motors, like pittmans, and we learned a lot about a smooth mechanical system when we tried to enhance things with electronics driving the motors. Weird irregularities in the mechanical system often made the “smart electronics” crazy.

Watch this video: http://www.youtube.com/watch?v=MX2xdJGZvG0

at 2:24 and 4:50 you see what a strange gearing and motor matchup did to the BEMF control of a DCC decoder. The characteristics of the motor and gearing became incomprehensible to the decoder and it surged like crazy.

In my opinion, the gearing is too high on this loco.

Just a few more points.

Regards, Greg

#66
TonyWalsham said:
Zubi. They don't overheat because they have a fan on them. They do draw more current than they should. That has been tested and proven. Mr Ames was testing tractive effort on brass or possibly SS rails. Our tests have been on filthy dirty mostly aluminium track which results in a lot more grip by the drivers. This equals more hauling power which requires more energy be burned which can overheat an ESC and flatten the batteries faster than it should, if the gearbox ratios were as originally specified and not half.
Tony, I am not saying that this is not the case. But if you want to convince me, please properly describe the experiments and show the results with all required descriptions to make your tests verifiable. Best, Zubi
#67

Since Zbigniew has provided us some calculations let me provide some raw actual data

The weight of the 2nd production K27 is a little over 13 lbs or 6 Kgs. Please note that the production models with metal tender trucks I have weigh a little more than the initial production one as an extra weight was added to balance the locomotives weight on the drivers

The following 1:20.3 scale speeds measured using a CRE-55465 ELITE TRI VOLTAGE POWER SUPPLY with a stock locomotive on stainless steel level track. Note since these were multiple stop watch measurements they are not exact. Please note that these speed differ slightly from what Zbigniew predicted.

33 scale MPH at 13.8 VDC
41 scale MPH at 18 volts DC.
69 scale MPH and at 23 VDC

The prototype K27 is reported to have a 45mph max speed which was limited by management to 30mph in later years. The K27 today runs in tourist service at 15-18mph

Tonight as an experiment I doubled the locomotive weight making the locomotive weigh 26 lbs or 12 kgs and ran the locomotive into a wall (max pulling power) at both 13.8 and 22 volts DC using the Elite supply on brass track.
At both voltages the wheels spun, the current draw at 22 Vdc was 3 amps continuous. Using the stock 13 lbs the current draw started at 2 amps and increased to 2.7 amps. I do not recommend doing this test with other locomotives as it puts a lot of load on the motor.

Since I have provided the variables anyone will be able to duplicate any of the results.

Now a personnel opinion. Gear ratio is indeed very important and Greg is absolutely correct that if the locomotive is delivered as a track powered DC locomotive then the locomotive should be evaluated using normal track power DC power supplies. My observations using popular Large Scale power supplies is that the stock out of the box locomotive has excellent pulling and slow speed performance. This observation seems to be the norm for track powered DC users based on information posted on various forums and in person discussions. The comprehensive review done several months ago in Model Railroad Craftsman seem to confirm this observation as well.

Note that the actual performance of DC supplies differ greatly and when you switch to a different electronic form of control such as a DCC decoder or what Tony and Dave place in locomotives the results may or may not be similar to the results observed using traditional DC track power supplies in large part due the characteristics of the electronic motor control device used.

Having a track condition and desired performance criteria we could all agree on would in my opinion help lead to better commercial models. Community agreements in this area would likely be very beneficial but also likely hard to agree on.

Is the motor/gearing in most every stock locomotive the optimal gearing that could be achieved? Outside a few models built by the expects such as Rod Miller very few commercial models have in my opinion the optimal motor/gearing. The NMRA built a locomotive test track some time back to test out the performance and efficiency of a locomotive. Only a very few achieved even reasonable results.

There is a lot that goes into a gear ratio and motor selection and any motor/gear ratio is a compromise of competing requirements. Today the speed range of the locomotive plays a very important part. Maximizing efficiency is also an important criteria as is minimizing amp draw across the models operating range and slow sped performance. Each motor has an efficiency curve and maximizing the range of the motor’s efficiency sweet stop is also a key element.

In my opining doubling the gear ratio for the K27 while satisfying some would cause significant problems with others. In my opinion this is not a viable solution.

Barry has reported that he is working on different gear ratio likely in the 1/16-1/20 range. No this gear change will not affect the number of cars that can be pulled unless the weight of the locomotive is increased. However, such a range may indeed have beneficial results in the efficiency area and in optimizing the current draw at common operating ranges. Myself, I will wait to see the actual test results on how speed, current draw, and performance is effected using a variety of power control options. If (and I believe the answer will be yes) the tests show improvements in key areas without overly compromising other performance areas(such as max speed) then there will be factual information which we can provide the manufacturers which hopefully can be used in the future.

Stan Ames
www.tttrains.com/tttrains

#68

ok, now I’m even more confused…

if the 14.whatever works so good for your K, why is the ratio now 28.something for the Mallet? are the two locomotives that different that they require 1/2 or double the ratio?

seriously, I really want to know…!

cale

below is an edit, please note:

Dave, Barry and Zubi…I appreciate your input into this entire debate, but since none of you can officially comment as a “consultant” or otherwise intertwined with Philly, please allow Stanley to respond. And Stanley, I’d like to ask that you spare me all the Mumbo-Jumbo from earlier post and provide us with a dead-level answer…something like, “the Mallet performs better with it’s ratio of XX.X than the K and it’s ratio of XX.X because __________________” you can fill in the blank.

Many Thanks!

ok, now I’m even more confused…

if the 14.whatever works so good for your K, why is the ratio now 28.something for the Mallet? are the two locomotives that different that they require 1/2 or double the ratio?

seriously, I really want to know…!

#69
Stan Ames said:
Since Zbigniew has provided us some calculations let me provide some raw actual data

The weight of the 2nd production K27 is a little over 13 lbs or 6 Kgs. Please note that the production models with metal tender trucks I have weigh a little more than the initial production one as an extra weight was added to balance the locomotives weight on the drivers

The following 1:20.3 scale speeds measured using a CRE-55465 ELITE TRI VOLTAGE POWER SUPPLY with a stock locomotive on stainless steel level track. Note since these were multiple stop watch measurements they are not exact. Please note that these speed differ slightly from what Zbigniew predicted.

33 scale MPH at 13.8 VDC
41 scale MPH at 18 volts DC.
69 scale MPH and at 23 VDC

The prototype K27 is reported to have a 45mph max speed which was limited by management to 30mph in later years. The K27 today runs in tourist service at 15-18mph


This tends to confirm what we have been saying all along.
The loco would have pretty much the correct top speed at 18 volts if the ratio was the designed for 1:30.
Why des it need to be faster than that?

Stan Ames said:
SNIP Now a personnel opinion. Gear ratio is indeed very important ............
Gotta love these personnel opinions.

Do they differ from personal opinions?

Stan Ames said:
SNIP In my opining doubling the gear ratio for the K27 while satisfying some would cause significant problems with others. In my opinion this is not a viable solution.

SNIP
Stan Ames
www.tttrains.com/tttrains


Would you care to elaborate as to exactly what the “significant problems” will be and who is likely to suffer from them.

#70

Stan, thanks for the actual data. I have two questions

  1. what is the weight of the locomotive only as is and with the extra weight (tender weight is irrelevant)
  2. could you provide actual voltage on the motor? I assume that the motor is not powered directly from the rails but through some electronics - this is why we need to compare voltage on the motor not on the rails. Also, strictly speakign we need to know if the motor is powered by DC coming out from the electronics.
    Best wishes from Tokyo, Zubi
Stan Ames said:
Since Zbigniew has provided us some calculations let me provide some raw actual data

The weight of the 2nd production K27 is a little over 13 lbs or 6 Kgs. Please note that the production models with metal tender trucks I have weigh a little more than the initial production one as an extra weight was added to balance the locomotives weight on the drivers

The following 1:20.3 scale speeds measured using a CRE-55465 ELITE TRI VOLTAGE POWER SUPPLY with a stock locomotive on stainless steel level track. Note since these were multiple stop watch measurements they are not exact. Please note that these speed differ slightly from what Zbigniew predicted.

33 scale MPH at 13.8 VDC
41 scale MPH at 18 volts DC.
69 scale MPH and at 23 VDC

The prototype K27 is reported to have a 45mph max speed which was limited by management to 30mph in later years. The K27 today runs in tourist service at 15-18mph

Tonight as an experiment I doubled the locomotive weight making the locomotive weigh 26 lbs or 12 kgs and ran the locomotive into a wall (max pulling power) at both 13.8 and 22 volts DC using the Elite supply on brass track.
At both voltages the wheels spun, the current draw at 22 Vdc was 3 amps continuous. Using the stock 13 lbs the current draw started at 2 amps and increased to 2.7 amps. I do not recommend doing this test with other locomotives as it puts a lot of load on the motor.

Since I have provided the variables anyone will be able to duplicate any of the results.

[…]
Stan Ames
www.tttrains.com/tttrains

#71
TonyWalsham said:
This tends to confirm what we have been saying all along. The loco would have pretty much the correct top speed at 18 volts if the ratio was the designed for 1:30. Why des it need to be faster than that?
Tony, it needs to be faster due to allometric scaling! Only a few people (protonerds;-) will want to operate it at prototypical speeds. Most will run it much faster without even realising this, to comply with the allometric scaling. Best, Zubi http://en.wikipedia.org/wiki/Allometric_law http://archive.mylargescale.com/forum/topic.asp?TOPIC_ID=46249&whichpage=4&SearchTerms=allometric

PS having said this, I would also be interested in the answer from Stan to your question “why does it have to be faster than that”, best, Zubi

#72

I guess you could say “allometric scaling” is an intellectual way of saying the WOW!!! factor.

How about you define who these “most” are you talk about.

#73
Zbigniew Struzik said:
Stan, thanks for the actual data. I have two questions 1) what is the weight of the locomotive only as is and with the extra weight (tender weight is irrelevant) 2) could you provide actual voltage on the motor? I assume that the motor is not powered directly from the rails but through some electronics - this is why we need to compare voltage on the motor not on the rails. Also, strictly speakign we need to know if the motor is powered by DC coming out from the electronics. Best wishes from Tokyo, Zubi
Sorry for being confusing.

  1. The actualy weight of the current production locomotive without tender is a little more then 13 lbs. When I added the additional weight this was only to the locomotive as well.

  2. The voltage to the motor in the cases of the reported numbers is the same as that to the rails less a minimal resistance due to rail wheel and wire resistance. The wires go from the track to the dummy board to the motor with no other electrinics inbetween.

One other note. The 9000 motor will take whatever current it needs to overcome a stall situation (a potential of more then 10 amps). If the wheels are not moving you are not providing the current/voltage the motor desires. I have observed electronics intended to be installed in locomotives that does not have the ability to properly control the locomotive.

Hope that helps

Stan Ames
www.tttrains.com/largescale

#74

I think Stan is talking about people, like me, who lose about 3 volts in their decoders, so 18 volts to the rails delivers 15 volts to the loco.

In my case, I have found a few locos that would not attain prototype top speeds when running from a 20 v RMS DCC system. I had my power delivery system modified to as high as the NMRA standard will allow, 24 volts, and this turned out to be really 23 volts to the rails, which means 20 volts to the motors.

The locos in question would then come close to prototype top speeds.

This situation can happen.

But, in this case it was a passenger locomotive that would not go over 62 smph… it will now got 92 smph. I rarely attain such high speeds, but these situations need to be considered.

In the case of the K, with my modified system and even adding a DCC decoder, there would still be a “surplus” of speed available in my situation.

So, I agree with Stan that consideration of what voltage different users will be able to “apply” is important, and can affect some users.

In this particular case, it does not seem to be a limiting problem in my opinion.

Regards, Greg

#75
Stan Ames said:
Sorry for being confusing.

  1. The actualy weight of the current production locomotive without tender is a little more then 13 lbs. When I added the additional weight this was only to the locomotive as well.

  2. The voltage to the motor in the cases of the reported numbers is the same as that to the rails less a minimal resistance due to rail wheel and wire resistance. The wires go from the track to the dummy board to the motor with no other electrinics inbetween.
    […]


Thanks for the explanation! Best, Zubi

#76
Zbigniew Struzik said:
Sory Tony, this has to wait;-)... as I would also be interested in the answer from Stan to your question "why does it have to be faster than that", best, Zubi
So what happened to the "allometric scaling" qualification?
#77
Cale Nelson said:
ok, now I'm even more confused....
There's a lot of that going around. The same guy said all these things JUST IN ONE (THIS!) THREAD:

“You are correct gearing is critical to proper operation.”

“Changing the gearing alone would have negligible effects.”

“Gear ratio is indeed very important”

and,

“if you were to replace the gearing from 1:14.5 to 1:30 the top end speed of the locomotive would decrease substantially/ likely by 1/2.”

“Myself I believe that prototype top end speed at 20 volts DC would be just about right”

"For the K27 I think a speed of 40MPH at 20 volts might be a good compromise "

"The following 1:20.3 scale speeds measured using a CRE-55465 ELITE TRI VOLTAGE POWER SUPPLY with a stock locomotive on stainless steel level track. Note since these were multiple stop watch measurements they are not exact. Please note that these speed differ slightly from what Zbigniew predicted.

33 scale MPH at 13.8 VDC
41 scale MPH at 18 volts DC.
69 scale MPH and at 23 VDC

The prototype K27 is reported to have a 45mph max speed which was limited by management to 30mph in later years. The K27 today runs in tourist service at 15-18mph"

Don’t feel badly. I myself am somewhat perplexed. Half of 70 is still 35, isn’t it?

Richard C.

#78
Stan Ames said:

33 scale MPH at 13.8 VDC
41 scale MPH at 18 volts DC.
69 scale MPH and at 23 VDC


Holy Crap! Doesn’t that strike ANYONE as excessively FAST???

Maybe I’m the exception, but on EVERY layout that I’ve OPERATED on those would be viewed as slot car speeds. Where are you going in such a hurry?

#79
TonyWalsham said:
Zbigniew Struzik said:
Sory Tony, this has to wait;-)... as I would also be interested in the answer from Stan to your question "why does it have to be faster than that", best, Zubi
So what happened to the "allometric scaling" qualification?
Tony, sorry, it is back now. You were too quick to reply! And I posted too quickly... never mind. Yes, this is the WOW factor, of course, but also the way we sense speed, smaller things tend to move faster and somehow we have this concept encoded in our perception. Unless you actually use a speedometer, I believe most people (including prototypically inclined;-) would sense higher than prototypical speeds as "right" or "looking good". But I would also like to hear the explanation from Stan, and also the explanation of what determined the change of the gearing ratio on the Mallet, as Cale is asking for - I think knowing this would help us a lot in this discussion. Best, Zubi
#80
TonyWalsham said:
This tends to confirm what we have been saying all along. The loco would have pretty much the correct top speed at 18 volts if the ratio was the designed for 1:30. Why des it need to be faster than that?
I am pleased that your findings and mine are indeed similar. That helps communicate

If the gear ratio was changed to 1:30 as you desire then the locomotive top speed would half and at 18 volts DC the speed would be 20MPH or a little more then the top speed of the Bachmann Shay.

No doubt many would find this an acceptable speed, especially the indoor folks or the modelers with small outdoor layouts.

If you do a search for K27 on youtube you will see how many actually operate the K27. It is a tad higher then that speed.

Most of my engineers on my railroad operate the K27 at about 30-35MPH on long runs. On a large layout this still appears slow and is much slower than what many large scale modelers operate their locomotives at.

TonyWalsham said:
Would you care to elaborate as to exactly what the "significant problems" will be and who is likely to suffer from them.
Like it or not the manufacturer of a mass market model needs to try to satisify the needs for as many modelers as possible. A K27 with a top speed that is much less then the prototype top speed and deemed by the modeler as to slow is just as bad as one deamed to fast.

To comminicate to a manufacturer you do so in speed at a specified voltage. Asking them to drop the top end speed by 10-20 percent is something that can be explained and justified. Dropping it by 1/2 to a speed much slower then many modelers want to operate it at is a non starter.

Let me use Greg for a moment as he is reading this thread. He increased the voltage of his system because the top end speed of his trains appeared to slow for what he wanted.

Speaking on behalf of the operators on my railroad the 2-8-0 has a top speed that is bairly adequate and most times that locomotive is run at full speed. The operators enjoy operatng the K because they need to pay much more attention to the actual speed than they enjoy acting more like an actual engineer.

I hope that explains the different views that one can have about speed.

Stan Ames
www.tttrains.com/largescale