Quote
As you were part of the consultations that took place during the design stages of the K-27, do you agree that 30:1 was the gear ratio proposed?

Do you agree that Bachmann decided that 29:1 was appropriate for the K-27?

If so, how come the K-27 has ended up with 14.5:1 and not 29:1?

Tony

I did indeed provide recommendations on the K27 to Bachmann and continue to do so.  I am credited on the Video for the K27 for this support.  The role of a consultant is to provide ideas in certain areas.  The design team consists of many engineers and many ideas and recommendation are considered but not all make the end product.  The K was designed for DC, DCC, and RC users and RC users indicated that they desired max prototype speed at 14.4 volts.  The higher the voltage the more batteries are needed.

What do you believe the top speed should be at 14.4 volts?

If the K27 were to have a gear ratio that is double what it has now the top speed would half or be about 16mph for your users or about 35mph at 24 volts DC

This might be fine for some users but others would complain that it was to slow.

When you can get consensus on what the top speed should be at the various voltages then together we can approach the manufacturers with a recommendation that can be designed to.

Stan Ames
www.tttrains.com/largescale

Greg

I agree but with large scale there is an additonal problem. What should the max DC voltage be from a standpoint of max prototype speed.

In the smaller speeds we have a spec of minimum max voltage  at full load of12 volts DC.  No similar voltage spec in Large Scale.

What should the max voltage be from a speed standpoint in 1:20.3

The top voltage is all over the place in large scale.

Many battery systems perfer 14.4 volts DC for max prototype speed (like the K27)Bachmann and Digitrax have apparently chosen 18 volts for their systems,  the DCC specs have chosen 22 volts, LGB and aristo have chosen 24 volts DC and some over 35 volts DC.

And if the manufacturer selects 24 volts as a prototypical max speed then many others at the lower voltages will have very slow locomotives.

In my opinion, its a problem that we the Large scale community need to come to grips with before we start critisizing any particular manufacturer or product

No simple answer here. 

Stan

ID=3
1-7-2008
7.20.2

With F0 on

Forward Front on bright rear off
Bachwards Front on dim read on

Hope that helps

Stan

Greg

Actually I had the dummy plug in for other tests but switching was no problem.

F10 says ID3

It is not a surprise that the lighting is different in different products.  Aristo-Craft has used different approached from time to time.  The concensus was to use the SD45 as the model of the correct version which is reverse to many other Aristo locomotives.

Stan
www.tttrains.com/largescale

I always enjoy the MR reviews because they provide actual drawbar pull, current load, and scale speed for the locomotive they review.  To me that provides a more objective review of a product and is invaluable information in the smaller scales.  Unfortunately. with the K27 review, it appears they must have used a wrong scale factor because the numbers do not match the numbers I get.

MR reports a max drawbar pull of 44 ounces.  I have no real way of measuring this to confirm this number and in Large Scale we all know the drawpull is effected by track type used and the age of the wheels.

MR reports that at 18 volts the K27 runs at 25 MPH.

Tony reports

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On 18 volts it gets up to about 80 scale miles per hour.

I had some free time this afternoon waiting for some cement to dry so I measured it myself.

I am using an Aristocraft CRE-55465 switching power supply that has a very good regulated voltage at 13.8 volts, 19 volts,  and 24 volts DC.

I do not have a lot of level straight track so my numbers can be off but they should be in range.

At 18 volts I measure a speed of 41 scale MPH.  At 23 volts 69 scale MPH and at 13.8 about 33 scale MPH.  These numbers could be off 10% or so but its a good start.

So what does this tell us.

1) the MR reported numbers are way off too slow

2) the Internet numbers are way too high

I believe the design criteria for the K27 was scale speed at 14.4 volts so it would appear that the measured numbers are a little fast but not that far off from what I believe the intent was.

Does this make the gearing optimal?  Not necessarily.

What we as a modeling community need to do is to develop a recommended speed scale speed table for the various scales.  That would provide us an objective number to measure the model against.

Prototype narrow gauge locomotives ran slow and many modelers enjoy operating their locomotives faster than the prototype.

If the manufacturer designs locomotives with scale speed at 24 volts DC, then modelers operating at 14 .4 volts will have real slow locomotives and those that enjoy faster locomotives will not get the desired speed at top voltage.

This is not a simple question and clearly one that needs the community to come together on.

Some like it fast some like it slow.  What we need to do is to quantify a speed range that is just right.

Hope that helps

Stan Ames
www.tttrains.com/largescale

Interesting discussion.  In my opinion, I believe that Tony and Bud have both correct and incorrect observations.

What’s missing is the voltage, control system they are using and a calibrated speed as one person’s slow is another person’s fast.

For example Tony says

Quote
it doesn't have any slow speed lugging power up even a slight grade.

Interesting observation.  I thought I would try it out.

On the level or running light on a 3% grade or running at full load on a 3% grade my K takes 78 seconds to smoothly go 1ft.  If I run the math correctly there are 5280 ft in a mile, that means about 260 ft equals 1 mile in scale of 1:20.32.  So that works out to about 0.2 scale miles per hour which is slower than most K27 operated at.  Note the pulling power on my railroad is limited by wheel slip and it is weight and not gearing that is going to affect wheel slip.

So clearly slow speed performance of is not a locomotive issue.  On my railroad my k27 has its top speed set for about 16 miles per hour which is rather fast for my railroad but well in the prototype range which for this locomotive would be a top speed of 30 mph.

Note that the performance on other systems will clearly vary.  For  example in DC the quality of the regulation and sensitivity of the power will also play a large role.

In order to have any type of serious discussion on speed one needs to have a graph of scale miles per hour vrs voltage.

The review in MR has one but I am not at all sure it is anywhere near correct as it seems to be a rather slow speed at 24 volts DC.

Once we can agree on the speed/voltage curve then we must discuss the max voltage.  Alas in large scale the max voltage is all over the place from 15 to 30 volts and the more voltage the more the max speed.

If you half the gearing you also half the max speed at any given voltage.

I am not saying the gearing is optimal or not as the a higher ratio may also result in a better motor efficiency.

All I am saying is that before we have this discussion we should be using real numbers and not subjective comments.  We should also have an understanding that user preferences are very different.  I have been constantly surprised at how fast some operate their locomotives yet also understand that the a mass produced locomotive has a wide range of users it must satisfy.

Stan Ames
www.tttrains.com/largescale

Nick

I use the QSI decoder with the K27 with absolutely no problems in 14 or 28 speed lighting.  And I have not found any production DCC decoder that has problems controlling any light or function in the K27.

If I were to guess I would believe that may not have the proper software downloaded in your decoder.  Some of the early versions of the software did not control the lighting properly.  Check to see if you have the current production release for the K27 software.  Also try operating the locomotive in reverswe to see if the lights work properly and also ensure that the lights are working properly in DC mode.

Hope that helps

Stan

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It's the second quote that seems to raise a question.  Why the pictures of the instal on MLS and not here on the Bachmann site?  As I mentioned above, this is the logical place for all the details that will be required to get the K-27 up and running and that would include any pictures.  Pictures of the installation will certainly help us all with converting our locomotives.

Jon

Perhaps I can answer your question.  The K27 has a number of innovative mechanical and electrical features.

Bachmann thought it would be useful to post a variety of installation examples for the K27.  These examples will include photos and be posted on the Bachmann WWW site and possibly other sites as well.

Hopefully by the week of Jan 7th they willl be able to place these examples on the Bachmann site.  Why the delay?  Simple.  Those involved in this effort are working across the industry to coordinate the examples to ensure that both parties agree with the installation write-ups.  It takes time to do this coordination and many companies take off this week.

There are a wide range of great products out there and the intent is to show a representative set of installations.

Following is a status of the effort.  Please note that these are representative installations and not all combinations are shown.  For example, while the Dallee installation could have been done for DC, DCC, or RC , DC was chosen for the write-up.

QSI Solutions (DC/DCC/RC) - write-up done and coordinated
Phoenix P5 sound with a generic DCC decoder (DCC/RC) - write-up done and in coordination
Dallee Steam Sound (DC/DCC/RC) - write-up done for DC sound installation and in coordination
ESU (DCC) - write-up in draft form
Digitrax (DCC) - write-up in draft form
CVP Airwire 900 with Phoenix 2k2 (RC) - in development
AristoCraft Radio Control  (RC) - deferred awaiting new product
SoundTraxx Sierra sound (DC)  - in development
Lenz Gold with Hybrid Drive - in development

As we move forward this forum will likely be the principle place where information will be disseminated but naturally discussions will take place on a variety of other forums as well. 

Stan Ames
http://www.tttrains.com/largescale/

Deb and I would like to wish The Bachmann, the folks at Bachmann and all the members of the Large Scale community a Merry Christmas and a hope that  during these 12 days of Christmas, Santa in his UPS brown sleigh brings to each what they desire.

Piece and Goodwill to all

Stan and Debbie Ames

Ok  time to perhaps clear up some misconceptions.

All systems (even DC) have two parts  The first part is the signal or if you will, the instructions to do something (in DC this is the amplitude of the voltage).  The second part is the power. Its the power that is used to run the trains.  These two parts can come from the same place (for example track DC) or from two separate sources (for example RC/Battery)

Traditional track powered DCC systems have both the power and the signal on the track.
Then there are radio control DCC systems such as Airwire which receives signal via radio and power via batteries or GWire which receives signals via radio and power either via the track or batteries.

DCC is really nothing more then a signal stream and it really does not matter how it is sent.  DCC can be track based, radio based or any combination.

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Jim and others. Sending DCC signals down the track is a nice idea. The problem is that if the track is dirty you lose your signalimple as that.  The better idea is using an R/C carrier and having the DCC as a signal component. Back in the early 70s another man and I did extensive experiments with battery operated R/C HO trains. It worked very well, the systemm was very simple, much like the Big Hauler's R/C unit but much more robust. That's whats needed. Hybrid drive might as well be battery operated for all of the trouble you go to.

japasha

Your belief on how this works is not correct.  You are assuming that with dirty track you lose the signal.  While true with some products it is not true with other product.s  If you have a decoder that has capacitance pickup you will pickup the signal on dirty track, through ice on the track, over leaves, or even if one rail is plastic.

The DCC signal actually has some very interesting properties. It goes through almost anything. 

The problem in the past was relying on power from the track.  Lose power and the trains stop.

With Hybrid Drive you combine the properties of battery control and DCC control.  Its not very difficult, and certainly from a locomotive perspective not much different then traditional RC/batteries.  The only difference is much smaller power sources can be used.  There are even small supercap modules now available that will power the locomotive for a few feet which is normally much more then needed (except for icy track where loss of power can extend for a long time).  It generally takes 15 to 30 seconds after I power up the layout for locomotives with supercaps or batteries to charge.

Quote
I had hoped this past summer to run some tests on using the rails to carry only the DCC signal but not the power to the locomotives.  The power would be supplied by on board batteries.

Jim

Based on your observations last year I did just that.  I used a Bachmann E-Z Command and even connected one lead with a capacitor so no power was on the track.

In this case I used sub C batteries and the operation time was as you expect the same as one would have with a RC system because the power was the same.

In reality you would want the full 1 amp on the track as normal resistance will consume some power.

I now have several locomotives that automatically convert from DC to track power DCC, to track signal DCC to Radio DCC.  If multiple DCC sources are present I chose the track signal to win but you can do it either way.

This also means that as the various control systems converge, it does not matter much anymore.

Hope that helps

Stan
http://www.tttrains.com/largescale

chenashea


The 4-6-0 is relatively easy to convert.  The hard part is removing the boiler to gain access to the motor and other wiring.

There are 7 to 9 screws to accomplish that.

Then remove the weight and the motor is easy to access.  Connect the track connection to the decoder and connect new wires to the motor to ensure the motor is totally isolated from the track.  The smoke unit is another two wires and the headlight connects to the decoder as well.

Check the pickups while you have it apart.  The overall performance of the locomotive can be greatly improved if you use some form of DCC Hybrid drive (on board backup power) 

Put it all back together and you are set to go.

Stan
http://www.tttrains.com/largescale

Kevin

When we redid the NMRA coupler height standards we were faced with no prototype standard (there is wide variation) so we filped a coin and went with the existing Kadee practice for coupler height which was in the valid range of protype coupler heights and matched existing modeler practice.

Bachmann used the NMRA standards when they developed their Fn3 product line.

I do not know what happened to Bruces figures on his page. I send him an email on this.

BTW the #1 scale kadee coupler represents a 7 1/2 inch coupler.  A 3/4 type D would be 6 3/4 while a 3/4 type E would be 8 1/4.

So for 1:20.3 modelers the Kadee sizes are the closest in the market for both 3/4 and full size couplers.

Stan

PS  the link to the Bruce's complete coupler pages is
http://home.comcast.net/~brmetcalf/rr/coupler.htm

For a good writeup on coupler sizes check out
http://home.comcast.net/~brmetcalf/rr/couplerp.htm
The Kadee G size coupler is a 10 1/4 inch coupler.  The Accucraft is a 12 3/4  inch coupler and the Bachmann is a 15 1/4 inch coupler.  For comparision a type D was 9 inch and a type E was 11 inch.

I use a sears craftsman screwdriver to uncoupler my cars.  Place it inbetween two cars and a slight trist and you are uncoupled.

All my crews get equipped with a screwdriver as it doubles as a device to clear out a turnout if ballast gets in the way.

Stan

In 1:20 Narrow gauge there were at least two common sized couplers used.  A full sized coupler (D&RGW) or a 3/4 sixed coupler (EBT)

The Kadee 830 coupler is about right for a full sized coupler and is a drop in replacement for the Bachmann 1:20.3 freight cars.

The 820 is a good 3/4 sized coupler. You will need to drill and tap a new hole if installing an 820 coupler on the Bachmann 1:20.3 cars.

I have found on my railroad which is outside that the 830s work better but others report good luck with the 820s as well.

Stan Ames

This Sunday September 2nd we will be holding our Fall Open House on our SJR&P garden railway from 9AM to 5PM. People traveling south from the National Narrow Gauge convention in Portland will find us only a short distance off Rt495 in Chelmsford MA.

The SJR&P is a narrow gauge Fn3 layout powered by DCC, Live Steam and Radio Control. Visiting Fn3 locomotives welcome, the only request is that the wheels be electrically isolated.

For driving instructions please email me off-line

Thanks

Stan Ames
SJRP Operations
stanames@comcast.net
http://www.tttrains.com/sjrp/