Large Scale Central

Does the gearing really not matter?

General Discussion
#81
Cale Nelson said:
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…!


Stanley, howabout an answer to the question I’ve asked twice now, and Zubi once? please see above…Yes Bruce it seems a very rapid pace to me…

thanks
cale

#82
Stan Ames said:

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.


Does the Bachmann Shay really go THAT fast? 20 MPH? Wow. I really can not imagine that. I typically run my Shay at about 6-10 MPH, and I thought THAT was fast. (Speed is measured with a scale speedometer car. I have seen the top end speed of my boxcab…and it CAN go 30 MPH, but I sure don’t like it at THAT speed. It looks very toy-like.)

#83
Zbigniew Struzik said:
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
Zubi, more than help, it could very well end the discussion for all time?
#84
Stan Ames said:
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.

[


The largest layout I’ve ever operated on was about seven scale miles in 1:20. I ran my BBT ten-wheeler there; I ran about 10-15 MPH and I might have exceeded 20 MPH in places, but it never appeared slow at all.

You need to slow down and enjoy the journey.

#85
Cale Nelson said:
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


This is a question you should ask Bachmann as it relates to a product they have yet to release.

Manufacturers have a top end speed in mind and set the gear ratio to achieve that speed. The motor the drive train and the wheels all play a role in that calculation. Locomotives with different motors, desired top end speeds or different diameter wheels will have very different gear ratios.

Once the locomotive is released I am sure that Zubi will be able to explain it in more elegant terms then I can.

Stan

#86
Stan Ames said:
Cale Nelson said:
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


This is a question you should ask Bachmann as it relates to a product they have yet to release.

Manufacturers have a top end speed in mind and set the gear ratio to achieve that speed. The motor the drive train and the wheels all play a role in that calculation. Locomotives with different motors, desired top end speeds or different diameter wheels will have very different gear ratios.

Once the locomotive is released I am sure that Zubi will be able to explain it in more elegant terms then I can.

Stan


http://www.youtube.com/watch?v=Qk-O9SM-tIU

#87

Cale,
one can only summise that, as a logging engine, operators have a perception (based on the Shay) that it should travel more slowly than a typical rod engine. Of course, as there was no prototype, actual top speed was a non event. To counter this theory, the Climax and the Heisler are little greyhounds on the rails.

    As to why the lower ratio was chosen,  do you really think that you will get a straight answer from anyone???????
#88
Stan Ames said:
Cale Nelson said:
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


This is a question you should ask Bachmann as it relates to a product they have yet to release.

Manufacturers have a top end speed in mind and set the gear ratio to achieve that speed. The motor the drive train and the wheels all play a role in that calculation. Locomotives with different motors, desired top end speeds or different diameter wheels will have very different gear ratios.

Once the locomotive is released I am sure that Zubi will be able to explain it in more elegant terms then I can.

Stan


Weird, I thought I saw a vid on the Bmann site of the Loco running at your house? How come you knew a great deal about the K long before it ever hit the shores of the US for distribution, but have no idea about the Mallet an estimated 1 month out?

sorry, that is another question you may have to try to avoid…oh well Ray, just below asked the same thing?

Manf may be interested in top end speed, but myself and most modelers (as witnessed here) are much more interested in a machine that operates through a full range of speeds…and very/most importantly to some/most…a close to proto speed.

Oh well, I guess this discussion will continue???

#89
Stan Ames said:
Cale Nelson said:
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?

cale


This is a question you should ask Bachmann as it relates to a product they have yet to release.

Stan, this puzzles me. You seem intent on responding to the gearing issue with the K as if you were either a Bachmann spokesman, or have some kind of personal stake in the matter. If this is the case you should be able to shed at least some light on why the Mallet, using the same motor, is apparently being given a different gear ratio (one which was originally recommended for the K).

On the other hand, if you’re not a spokesman for Bachmann and have no stake in the matter, why not ask that questions about the K be directed to Bachmann, just as you have responded regarding the Mallet?

I don’t have a dog in this fight, I’m just curious.

#90
Tim Brien said:
Cale, one can only summise that, as a logging engine, operators have a perception (based on the Shay) that it should travel more slowly than a typical rod engine. Of course, as there was no prototype, actual top speed was a non event. To counter this theory, the Climax and the Heisler are little greyhounds on the rails.
While a very well thought out and reasonable hypothesis, this text from Bachmann's website provides some insight into their thinking on the model, and I'm not sure it supports it:

“The 1920s marked the end of a logging push in the northwestern United States, where lumber companies needed more powerful engines to efficiently handle greater load capacities and quicker turnaround times demanded by the ever-increasing distances from the logging camps to the sawmills. In 1928, Biles Coleman Lumber Company approached the Baldwin Locomotive Works with a request for a narrow gauge 2-6-6-2 capable of handling operations on a recently developed twenty mile logging line. Baldwin responded with a scaled down version of an existing standard gauge design, which was promptly approved by Biles Coleman.”

Sounds like the geared jobs being so slow was part of the problem…

Matthew (OV)

#91
Stan Ames said:
I am pleased that your findings and mine are indeed similar. That helps communicate
The ability to communicate requires the respondee to actually listen, pay attention and comprehend. So we can agree on something.
Stan Ames said:
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.
Yes. If they need to go faster up to say 30 mph then the would need to add extra voltage. Most controllers will get close to or exceed 24 volts. By your own admission elsewhere you agreed the speed ratio would not be all that exact anyway do to freeing up the load by having a lower ratio. My experiments with numerous K-27's has shown they go plenty fast enough on less than 14 volts output of the controller. I know of no one with anything like a graded or curvy track that has run them flat out.
Stan Ames said:
SNIP 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.
I can only assume you lowered the voltage output from the on board decoders, otherwise they would be ending up in the boonies very quickly.
Stan Ames said:
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.
I guess that is an admission that catering for the great unwashed is more important than getting it right and relying on quality to sell a product.
Stan Ames said:
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.

SNIP

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


So all those operators of Accucraft locos, with most of the locos with roughly 30:1 gearing, are wrong to accept that ratio?
Why don’t you trot along to a forum that specialises in big Accucraft locos and try and convince them to change the gearboxes in their locos because they don’t knowhat they are missing out on.

Oh!!! silly me. You did that already. :wink:

#92
Barry Olsen said:
Zubi,

There are no values given in Watts on the Pittman data sheets. I suspect that the watt values are a combination of other values calculated to produce the watt values. If you an direct me to the values needed to produce the elusive watts, I’ll try and find them for you.

Barry - BBT


Barry, thanks! I found 9000 series specs here: http://www.clickautomation.com/products/index.php?func=show&pid=345&cid=143 If this is the correct motor, its resistance is 2.96 ohms, and the torque constant (Kt) = 5.17 oz-in / Amp, so power dissipation at the continuous torque level is only 4.1 Watts but at the point of stalling the dissipated power will be 188.5 Watts (by the way the current at this point is 7.98 Amp so is 20% less than 10 Amp which Stan Ames mentioned but obviously still very high). Obviously 4 Watts does not require any cooling fan. Stan measured 2.7 Amp at the point of slipping at 22V for stock locomotive - this produces 21.6 Watts of heat, and I would say that this also does not really require a cooling fan (for me the threshold is 25 Watt but this depends on the enclosure, type of mount, etc. ). The locomotive with extra weight draws 3 Amp at the point of stlipping in Stan’s test, and this produces 26.6 Watts. As you see from these figures, there is no real reason for the fan even at the point of slipping. However, if you look at the figure at the point of stalling - this is nearly 200 Watt - you can cook with this kind of power and while in normal operation there may be no need for cooling perhaps Bachmann engineers added the cooling fan to account for the worst case scenario (or just to be on the safe side) on what is considered by some who buy it as a toy and which therefore should be fool proof;-)… Best, Zubi

#93

The talk of running to scale speed has drug me into this discussion. Took me a while to find it, but I new the speed was in print somewhere about how fast the trains run on the Cumbres and Toltec. In the Introduction of “Ticket to Toltec” by Doris B. Osterwald it states - “The train travels about 12 to 22 miles per hour”. Running those model engines at speeds greater than that is slot car racing. And I would certainly think that running a geared engine faster than 10 mph is really pushing it. But then again everybody should be able to play with their toys the way they want to.

#94
Stan Ames said:
[...]

Once the locomotive is released I am sure that Zubi will be able to explain it in more elegant terms then I can.

Stan


Stan, thanks but I thought that you would save me some time;-)))…
Well, anyway, we know that the drivers on the Mallet should be 42" which is 5% larger than on the K-27. We also know that at the same high pressure cylinder size the Mallet had some 15% smaller tractive effort and was heavier (weight on drivers) so my guess is that it would have been slower (if built of course). My guess is that this difference in max speed was somewhere between 15%-25% but if anyone can give a better, more educated guess, please do!
Now we need to know the motor type - so please confirm if this this is the 8000 motor (I assume that you know this).
http://www.clickautomation.com/products/index.php?func=show&pid=335&cid=142
Thanks, Zubi

#95
Zbigniew Struzik said:
Stan Ames said:
[...]

Once the locomotive is released I am sure that Zubi will be able to explain it in more elegant terms then I can.

Stan


Now we need to know the motor type - so please confirm if this this is the 8000 motor (I assume that you know this).
http://www.clickautomation.com/products/index.php?func=show&pid=335&cid=142
Thanks, Zubi

He told me to ask Bmann about the gearing, it is their product…if he doesn’t know the reason for the gearing; it’s doubtful he’d know the motor specs?..

#96
Cale Nelson said:
He told me to ask Bmann about the gearing, it is their product....if he doesn't know the reason for the gearing; it's doubtful he'd know the motor specs?......
Cale, of course one can ask Bachmann too, I just do not quite feel like wasting much more time on this issue at the moment, I had enough fun doing the exercises for some time to come;-))) well, a couple more weeks and new (happy?) owners should be able to test and dissect their new Mallets... If the motor is indeed comparable with the 8000 series which I found, I would not be surprised at all that the gearing is twice as high numerically on the Mallet, essentially all parameters are different by factor two when compared with the 9000 series. Additionally, the Mallet has 5% larger drivers and it should travel up to 25% slower, this would account for the twice higher numerical ratio on this locomotive. But let's wait or if you wish go ahead and try to get the motor info from Bachmann! Best, Zubi
#97

I’ve been following this thread for a while now, and I’ve learned a lot. Mostly I’ve learned that I want to avoid ever venturng into 1:20

But it seems to me, and I speak as a total novice with little or no experience, who has never beheld a Bachmann K in real life, much less run one–that this argument is yet another instance of the track power vs. battery war. The problem with the stock K is that as geared, it draws too much current and runs the batteries down too soon. Am I wrong about this? It seems to me, based on Zbigniew’s argument, that if you are running on track power it’s not going to matter, and if you are running on battery it’s only going to matter in that it runs the batteries down sooner than it would if you geared it differently. Which makes it less than optimum, and suggests that it was designed with DCC or DC in mind

Is that what all this heat and insulting is about? Because if so, it makes sense. If I’ve learned one thing in my year of so of engagement in this hobby, it’s that Battery vs track power is a holy war, in which the stakes are extraordinarily high, and that no prisoners may be taken and the enemies fields must be sown with salt.

#98

Hi Guys,
I have a copy of Model Railroad News, March 2008 which has a review of the K 27 by John Sipple. It states that the loco weigh’s 12 lb 2 oz, tender weighs 4 lb 4 oz. He states she’s a hard working puller posting 3 lb 4.8oz of pull for a whopping 27.22 percent tractive efficency.
Also stated, This is a bull-gear drive so there is no worm gear and pushing the locomotive will cause the drivers to turn. When you attempt to roll it you will feel the friction of gear reduction, however. I actually prefer this arrangement and compliment this model’s designers for it. I found I could stop the locomotive with a heavy train on any sort of hill and it would stay putthere so this isen’t what you would call a free rolling situation.

Can someone explain what a bull-drive is and how does it work without a worm gear??

In mho this is a good review of the b-man K, anyone thinking about buying one should check this artical out.

Chuck

#99

A John Deer “Bull Drive Gear”…

(http://i2.ebayimg.com/02/i/000/f7/c7/13dd_1_sbl.JPG)

From Wikipedia, the free encyclopedia said:
The term bull gear is used to refer to the larger of two spur gears that are in engagement in any machine. The smaller gear is usually referred to as a pinion.

Methinks it still uses a worm to drive a spur gear, but it could be done with a pinion gear mounted on the motor shaft. I’m sure someone here has had it apart and can confirm the gearing arrangement.

#100

Jon,

So, where’s the bull? :smiley:

Mike,

I suppose that you could say this is a holy war, and that villages must be burned and the fields sown with salt. That said, I get the notion that the K works fine at Warp 8-10, but not on 1/4 Impulse, even with DCC. Since many of us here are more interested in operating our railroads as the big boys do, that requires reliable slow speed ability. To mix a metaphor, it is as though a shipbuilder required the captain to approach the pier at Flank Speed, because the ship’s engines are not reliable at anything less.