# Regearing Bachmann K27



## RIO WARREN (Dec 9, 2009)

I have raised this topic on a previous time and at that stage there was nothing avaliable
I am aware of the recently avaliable K&R reduction drive fitted to the Bachmann motor, but have been advised that there is a further development using replacement gears and saves stripping the locomotive down and is more economical as I have several locos to be changed
Any advise on these developments and purformance of such units would be greatly appreciated

RIO WARREN


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## steam5 (Jun 22, 2008)

Now that a good product is on the market I doubt something else will become available. I have and R and K gear box, haven't installed it as yet, but it looks nice and it got a good review in Garden Railways Mag. 

If you have several maybe you could sell a loco and put the funds towards the R and K product to fix up your other K-27s, just an idea. 

Alan


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## RIO WARREN (Dec 9, 2009)

thanks for the advise I read the review in Garden Railways and it looks good but I had been advised of a replacement gear set that I cannot find any thing about,hence this posting so I could explore the options if the advise given was not incorret which now appears to have been the case 
Rio


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## Steve Stockham (Jan 2, 2008)

I believe that the replacement gearing that you are referring to is probably the one that Barry of Barry's Big Trains (BBT) is developing. The last I heard, it was still in developement. They had some questions about the robustness of the off-set reduction gearing which they had considered as well. I have one of the reduction gears in my K-27 and it's _not _a difficult install at all! The improvement in slow speed and the reduction in surging is so much more than I had hoped for! There _is_ one small drawback and that is an increased gear noise but this is quieting down somewhat as the engine gets run more and more. I will say that my Sierra digital sound system pretty much covers any gear noise when running outside so this is really a non-issue for me.


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## RIO WARREN (Dec 9, 2009)

Thank you for the info I have just about made my mind up to go with the the K&R unity as it seems to cover my needs and it is probably better than sitting around waiting and doing nothing 
Rio


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## chuck n (Jan 2, 2008)

I did the conversion on my two Ks last Summer. I am very pleased with the results. The gear noise does go down with time. Not to no gear noise, but acceptable.

Chuck


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## Westport (Nov 28, 2009)

Hi, Probably a dumb question but are the Bachmann K-27 gearing problem and other earlier issues with the engine still a concern? The C-19 sounds like it might be a better choice if I understand the ads re description of its engine and and gears but I would like the K for my layout if it could deal with the grades without the gears breaking as they did with my Bachmann Connie. 
Myron


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## TonyWalsham (Jan 2, 2008)

The second run did fix iffy tender trucks with much better metal side frames and the loco has the better fitting driver counterweights mounted. 
Otherwise the gearing is still the same. Too high. Fine on the flat but with a load can bog down going up grades and run away down grade. 
The chuff timer is wired back to front. Easy fix. 
Smoke will be a bit wispy unless you reverse the fan in the loco. Not an easy job.


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## Westport (Nov 28, 2009)

Thank you, Tony for the information. As both a r/c battery and straight battery user, I don't use the smoke units on my engines as it reduces the use of batteries by half for my electric engines-Aristos. LGB, and Bachmann, and the chuff timer is not really a concern for me, athough the Consolidation does sound blurry down grade. I had to have the gear replaced in the Bachmann Consolidation because of grade and load. My Accucraft live steamers don't seem to have that problem! 
Thanks again, 
Myron


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## East Broad Top (Dec 29, 2007)

I had to have the gear replaced in the Bachmann Consolidation because of grade and load. 
Well, that was more a factor of a weak gear design than grade or load. There's a distinct reason Bachmann finally introduced a brass replacement gear... No worries about broken gears on the K-27. All new design with brass gears from the start. 

Allow a slightly different perspective on the K-27 gearing. There are number of folks (like Tony) who make the case that the loco is geared incorrectly; that it bogs down going up hill and speeds up going down hill. Yes, the loco does display those characteristics. But so do many other locos. My venerable LGB mogul is just as bad as my K-27 in that regard, in fact they're closely matched in terms of overall speed and performance on my railroad. My dad's railroad has some extreme grades--4% or greater in some places--and there's not a loco in his roster that doesn't slow way down pulling a train up the grade, then take off like a rocket going back down. That's physics. Either you level out your railroad to get rid of the grades (not always practical) or you ride the throttle (just like the prototype--and like you must do on a live steamer.) Stock out of the box, the K-27 is one of the smoothest running locos I've had the pleasure of running. On my railroad (2.5% maximum grades) it's very controllable. Yes, it does speed up a bit heading down grade--the same as all my other locos. I'm typically a hands-on operator, so I'll just adjust the throttle to match the situation. Switching the sidings, the slow speed control is very smooth, certainly in the top tier performers. I run battery power (14 volts), and at full throttle, it hits around 35 mph. With track power, it pushes 45 - 50 mph--fast for narrow gauge, but certainly plausible. (There's a lot of "unsubstantiated opinion" about what the true top speed of these locos was, as well as differing opinions on whether manufacturers should try to match a model's top speed to "typical" speeds or true "top" speeds of the prototype. "Top" speed for steam locos is typically estimated as 1.1 to 1.5 times the driver diameter, so a K-27 would have a theoretical top speed between 45 - 60 mph). Given those operating characteristics and prototype factors, _in my opinion_, there's nothing that stands out in the operation of this loco stock out of the box to where I could describe the gearbox as flawed when compared to other locomotives on the market. 

Because it's comparable to others doesn't mean it can't be improved. R&K Products sent me a replacement gearhead drive for a product review for _Garden Railways_ magazine. After installing it in my K-27, the performance was markedly improved. It started moving at a slower throttle setting--still with very good slow speed control, and its top speed at 14 volts was a very sedate 20 mph. On track power, that would jump to about 35 mph top speed. (I find that I like to see my trains run between 10 - 15 mph.) There was no appreciable speedup or slowdown on the grades, and it maintained a more constant speed through my 5' radius curve which previously had bogged it down a bit. It's an improvement to be sure, with the attendant trade-off of gear noise. Whether you find that objectionable will likely depend on your own ears, and whether you've got sound installed which would mask the gear noise. I've heard louder locos. 

One other consideration, too, is how you're going to be controlling your K-27. Some advanced throttles have cruise control circuitry that will maintain a constant speed over changes in grade. Two battery R/C boards that come to mind are QSI and Airwire's G-2. Both of these systems use feedback from the motor to maintain a constant speed, and both systems work very well, even with extreme changes in grades. Other DCC throttles have similar/identical features if you can avail yourself of them in your operating environment. If you can use that, you may find that you don't need to upgrade the gears. 

My advice would be if you're thinking about a K-27, get it and run it on your railroad. If you are happy with how it runs, go with it. I know many folks who have these locos running stock and are nothing but pleased with their performance (as I was with mine). If your grades are more extreme and you find its tendency to speed up going down hill to be an issue, then there are options for "taming" its performance available to you depending on whether you want a mechanical fix (gearhead motor) or electronic (throttle with cruise control). 

Later, 

K


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## Westport (Nov 28, 2009)

K, thank you very much for the fulsome information and now I intend to add a K-27 to join the Bachmann Connie. I have always tried to focus on narrow gauge with some slipups to 1.29th (BCR and CPR) and the earlier and now mostly unused LGB engines/cars, so I now have something to save my loonies for! I have one demanding grade (2-3%) on the layout but all the locos of any make, even live steam, do not stall on it. Thank you again, for the helpful response. 
Myron


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