Kernow Model Rail Centre to produce GWR 1361 0-6-0 Saddle Tank

[Gerald Henriksen]

I'm not aware that Oxford scanned the Dean Goods, in my discussion with them at the ToyFair 2016 no mention was made of it,

 

All the above however doesn't cover the incorrectly placed cab steps which have been there since day one of the CADS, regardless of the primary data source. Using the 'amateurish mistake' analogy applied to the team regarding the Dean Goods CAD detail reviews, surely the same comment is just as valid here? 

 

In your original reply you included the following quote:

 

 

 

t's a more than fair point to remind us that over the years umpteen models have had their faults but Oxford has managed at least one thing never, I'm sure, achieved previously  in their Dean Goods and that is misreading the results of and data from a scan of the prototype

 

scan of the prototype is a 3D scan.  Now it is possible that the person you were quoting is incorrect.

 

My point though is that adding details that don't exist on a prototype is a step further into the amateur category then steps, which while not apparently perfectly in place are at least close.

[JSpencer]

There are two current Bachmann steam products I am aware of with the 2nd and 3rd axles geared together, the 9F and G2A. No widely reported problems with their running that I am aware of, and the rods between the gear coupled wheelsets don't appear to have more 'slop' on the crankpins than is usual, nor do they take up any deviating angle from the general line of the coupling rods. (Having had the pleasure of watching these 9Fs in particular in very regular action on the layout over ten years, never seen anything to suggest a problem.) But that's only two axles that are both rod and gear coupled.

 

Ideally, if going with both rod and gear coupling of wheelsets, then the gear teeth should be phased coincident with the phasing the rods enforce, to avoid the requirement for excessive clearance 'somewhere': if on the crankpins, then with the resulting possibility of 'off-angle' rod positions as they are only going along for the ride. Simple enough in principle on a jig assembly tool, for each wheelset to have the axle with the gear on it presented at a consistent tooth position relative to the crankpins as the two wheels are pressed on quartered.

 

I have 2 Bachmann 9Fs and one G2A, all more than 10 years old now (or getting close to it). No running issues at all. From memory, most N gauge models use all gear trains.

 

I really do not think that in itself causes an issue. The fact that DJM prefers this, and some have had issues of a kind they feel they have not seen before, is too easy to associate to it being with the gear train just because it is the first visible design aspect difference with other makes designs. On the 14XX thread, one person took out part of the gear train and found the same problem. The issue clearly was the top gear tooth locking the worm of the motor meaning maybe the motor lacks mass/power to overcome it and/or the worm is too fine and/or its missing a lot of lubricant in that area (or a combination of any or all three).

Its like the famous test between air and vacuum brakes. On the particular day, the Vacuum brake performed better and was chosen as the system for the railway. Had the air cylinder been just as large as the Vacuum one, it would have been a different story.

 

Andy Y already commented that he found no issues of stalling going down descent for this loco. I don't think I've seen the same stalling issues reported on the O2 and Well tank neither that use the same gear train. The Well tank copying a practice from Dapol (only the motor changed), itself found on the sentinal tank (which has no roding).

 

From a quartering perspective, the gears will need an even number of teeth in each quarter perfectly centered over each quarter. If they are not then there is a huge risk that assembly will mis-quarter the wheels that cannot easily be corrected. Has anyone counted the teeth on the these gear wheels? If it divides squarely by 4, there is no risk.

[sparaxis]

There are two current Bachmann steam products I am aware of with the 2nd and 3rd axles geared together, the 9F and G2A. No widely reported problems with their running that I am aware of, and the rods between the gear coupled wheelsets don't appear to have more 'slop' on the crankpins than is usual, nor do they take up any deviating angle from the general line of the coupling rods. (Having had the pleasure of watching these 9Fs in particular in very regular action on the layout over ten years, never seen anything to suggest a problem.) But that's only two axles that are both rod and gear coupled.

 

 

 

And they are not the only Bachmann locos that have axles geared together, the Compound and D11 do as well, And I suspect the Dukedog. (I'm not in a position to check right now) I think the GNR Atlantic was designed like that but didn't get them in the end. Some Fleischmann and Brawa locos have two axles geared.

 

But, and this is a big but, this is where it gets interesting. When two axles are geared, the gear train can be set up so that the initial drive into the gear train is equi-distant between the two final axle gears. (With respect to the number of sets of meshing teeth that is.) so there is the same amount of backlash between the first gear and both axle gears. When you drive three or more axles from "one end", there is progressively more backlash and slop in the geartrain the further you get from the first axle. 

 

Notice that Rapido (Pic Above)  has arranged their gearing so that the end axles have the same number of gears between them and the worm-wheel. This means that both end axles will rotate together, allowing smaller clearances in the side rods. The drive to the centre axle is shorter, and thus the centre axle will turn slightly before the others, but this can be dealt with by larger clearances in the rods at the centre crankpin.

 

With good assembly this will work just fine, but I prefer rod drive,with jointed rods as that allows axles to be sprung or compensated. For example, the Fleischmann BR78 4-6-4t, has gear drive on the trailing axle, a sprung centre axle, and a "pendular" first axle, allowing it to rock around the centre-line of the loco, giving a true three-point suspension.

 

Trying to do that with geared axles gets really complex, but it has been done, i.e by Teichmann (Below)

Edited September 27, 2017 by sparaxis

[UMinion]

A couple of shots to show that there is actually a recess for the rear wheels beneath the firebox/cab which indicates the factory designed a form of recess in for the wheel/flange clearance.

 

I would hope so. Imaginary solid splashers would be properly mad. Any chance you can take a dead side on view andy with the centre point the bottom of the underframe? It looks from your pictures that the actual wheel treads are above the bottom of the floor? Is the 'compromise necessary because the wheels are too big anyway? (Wasn't that a problem with the GWR 0 4 2 as well from the same stable?) Edited September 28, 2017 by UMinion

[cctransuk]

That's pragmatically close enough in my view, John.

 

1361-back-end.png

 

The dimension from rail to top of cab, given on the drawing as 11'-7'' (46.3mm. at 4mm. scale), measures 46.3mm. on the Heljan model.

 

The model's wheel diameter is 14.7mm.; the prototype's is 3'-8'' (14.66 at 4mm. scale).

 

So, I can detect no significant departures from scale with the Heljan model as far as these critical dimensions are concerned.

 

Nonetheless - no splashers.

 

Regards,

John Isherwood.

[Miss Prism]

Note the footplate does not extend into the vertical space of the springs:

 

 

 

[New Haven Neil]

Yes - the Heljan ones are much too high above the footplate, now I look.

[cctransuk]

Yes - the Heljan ones are much too high above the footplate, now I look.

 

Errr - have you read #433?

 

Regards,

John Isherwood.

[Oldddudders]

Errr - have you read #433?

 

Regards,

John Isherwood.

Does that mention springs and footplate relativity?

[cctransuk]

Does that mention springs and footplate relativity?

 

No - but since the post had no quote, and followed one which I took to refer to the model as a whole, my misunderstanding is perhaps not unreasonable?

 

Regards,

John Isherwood.

[PMP]

Let's face it, shortening the spring supports on the Heljan version will be a far easier job than removing and making good four splashers, particularly if like the other DJM steam designs they're not straightforward to disassemble.

[dibber25]

I think you've lost me - but I don't have either model here to look at in order to understand how the cosmetic springs come into this. I did spot three Kernow boxes in the Model Rail in tray yesterday, and I couldn't resist having a look and a little 'play'. I've just done a huge review of something else,though, so I think I probably won't be the one to review these. (CJL)

[New Haven Neil]

Errr - have you read #433?

 

Regards,

John Isherwood.

 

Not biting, sorry.

[cctransuk]

Not biting, sorry.

 

Please - see #438; a simple misunderstanding of your post.

 

Regards,

John Isherwood.

[New Haven Neil]

Please - see #438; a simple misunderstanding of your post.

 

Regards,

John Isherwood.

Accepted.

 

Neither of these models are perfect, but we don't have to cast our minds back far to see they are very, very much better than anything we had only a handful of years ago. That so many missed the splashers 'way back when' I do find a touch amusing, given the knowledge base these people do genuinely seem to have.  It can't be that big a deal then, can it?  I know you can't 'unsee' them, but still.....maybe it's just me.

 

The perfect RTR model has yet to be seen, the Sutton Class 24, which was a quantum leap, took a lot of flack regarding vent panels yet is probably the joint best (with the Dapol Western) 4mm diesel model yet.

 

One thing I don't really get is the coreless motor thing.  In the US scene these have been seen as the right thing for years - and most N gauge models have them nowadays. I have an Austerity and it runs like anything else really - DCC admittedly - but there isn't an issue, it just runs. Quite well in fact.  No issue.

[PMP]

Like John above I too didn't follow your post, hence agreeing with his original response.

[No Decorum]

One thing I don't really get is the coreless motor thing.  In the US scene these have been seen as the right thing for years - and most N gauge models have them nowadays. I have an Austerity and it runs like anything else really - DCC admittedly - but there isn't an issue, it just runs. Quite well in fact.  No issue.

I have expressed delight that, contrary to expectation, Kernow’s Bulleid diesels will not have coreless motors. Perhaps I should amplify my view. I have experienced problems with models fitted with coreless motors but that does not necessarily mean that the motor is at fault. My O2, for example, has coupling rods which assume all sorts of odd angles. I observed the same on a picture of an X4XX. The likely cause of this is conflict between the gears and the rods. It is also being said that there is nothing wrong with geared drive to all driving wheels on a locomotive fitted with coupling rods.

 

That does not convict the coreless motor or exonerate it. Neither does it mean that there is anything wrong in principle with geared drive and coupling rods used together. However, in practice, it can turn out differently, particularly if tolerances are not fine enough. To take an example rather less emotive than the coreless motor, Hornby in its “design clever” experiment started to fit three-pole motors instead of the five-pole skew-wound motors it had used before. It was claimed at the time that a three-pole motor is as good as a five-pole one. That may be true in principle but some of us found that the three-pole motors used were awful. I have since had a shock to my system in that a Hornby five-pole, skew-wound motor was not a good runner. The replacement was much better.

 

I’m glad your Austerity runs well. I have four. They are beautifully decorated and, whilst not by any means awful runners, I have found them adequate rather than good and a bit noisy. My 71 is not a good slow runner either. It has its good qualities but its running is no match for the Hornby.

 

We have the means to produce models which run smoothly and quietly. Why muck around?

[Covkid]

The perfect RTR model has yet to be seen, the Sutton Class 24, which was a quantum leap, took a lot of flack regarding vent panels yet is probably the joint best (with the Dapol Western) 4mm diesel model yet.

 

 

 

It is a good job we are all different then !!! I think the Dapol D63xx was a far more realistic model with a correct looking "face". Even though I have a Dapol "wizzo" I am still unhappy about the headcode box area and the central windscreen glazing bar and find my D6316 a more attractive model overall.

Edited September 28, 2017 by Covkid

[brushman47544]

I have a Dapol "wizzo" I am still unhappy about the headcode box area.

 

If you've fitted the headcodes supplied with the model, then yes the area looks odd because they're too small. I've used the correct size headcodes (from precision Labels) and the improvement is immense.

[New Haven Neil]

I have expressed delight that, contrary to expectation, Kernow’s Bulleid diesels will not have coreless motors. Perhaps I should amplify my view. I have experienced problems with models fitted with coreless motors but that does not necessarily mean that the motor is at fault. My O2, for example, has coupling rods which assume all sorts of odd angles. I observed the same on a picture of an X4XX. The likely cause of this is conflict between the gears and the rods. It is also being said that there is nothing wrong with geared drive to all driving wheels on a locomotive fitted with coupling rods.

 

That does not convict the coreless motor or exonerate it. Neither does it mean that there is anything wrong in principle with geared drive and coupling rods used together. However, in practice, it can turn out differently, particularly if tolerances are not fine enough. To take an example rather less emotive than the coreless motor, Hornby in its “design clever” experiment started to fit three-pole motors instead of the five-pole skew-wound motors it had used before. It was claimed at the time that a three-pole motor is as good as a five-pole one. That may be true in principle but some of us found that the three-pole motors used were awful. I have since had a shock to my system in that a Hornby five-pole, skew-wound motor was not a good runner. The replacement was much better.

 

I’m glad your Austerity runs well. I have four. They are beautifully decorated and, whilst not by any means awful runners, I have found them adequate rather than good and a bit noisy. My 71 is not a good slow runner either. It has its good qualities but its running is no match for the Hornby.

 

We have the means to produce models which run smoothly and quietly. Why muck around?

 

 

Lets not complicate it by joining coreless motors and geared drives - the two things can be mutually exclusive, and are not related except in DJM braded locos currently.

 

The best running loco I have (from about 45 USA and 60 UK outline) by far is a Korean brass ALCO diesel - with a coreless motor.  It is silent, runs from barely perceptible to a scale 70 or so (about right) and can pull a large scale house down.  The running of the Austerity is about the same as my USA tank, but is slightly noisier admittedly - no doubt the geared drive - however as it runs more it is getting quieter.  There is no difference in speed control.  My 71 as yet is still in the box!

 

I have seen an opinion regarding the reason for more coreless motors being used, and this it that due to their much greater use in industry meaning they are more common and therefore cheaper.  Indeed, that the iron core motor maybe on its way out due to the low numbers made making them uneconomical to manufacture. We await developments!  Early adopters may end up being ahead of the game.

 

Drifting back on topic - shock - the cab steps are a bit of a howler though.  How come no-one saw that?  NO-ONE......   Easily fixed but you shouldn't have to.

[Ian Hargrave]

 ...again.I will be very interested in your comments on the running of your Class 71,Neil. Mine will move splendidly at slow speed,even with a load of 8 lit Hornby Pullmans +baggage van.......but runs out of clout as I increase power and even on max.current  (dc analogue) cannot reach acceptable scale speed above 45-50 mph.Others I have spoken with report the same. I am certainly no expert with regard to motors but I would hazard a guess that the installed unit is simply insufficiently powerful for the job.

 

My only other experience with coreless motors is with Faulhaber motors (quite small) installed in a coupe of Trix units ..Spanish Brotli Bahn being one.No problem there.

 

I have on order a Kernow DJM D6XX Warship. I have spoken with Chris Trerise ( I have posted on this elsewhere) with regard to my experience with the 71.He assures me that he will test it under load before release.

I certainly would not write off coreless motors but would ask.....Which coreless motor is appropriate for the model it is to be installed in ? Put another way...is it up to the job?

[JSpencer]

Coreless motors are being incresing used because they are lighter, offering the same power (at least) size for size with an iron core motor of the same characteristics. Great for drones and machines requiring lighter, fast reacting (no iron mass to overcome) motors but for model railways, we are not expecting to suddenly reverse our locos, nor do we wish our model locos to be light.

 

Thereafter there are different grades of coreless, some used in model locos are skew wound, 5 or more poles like their iron cored cousins and cost just as much to make (some are conceived to give feedback in a similar way as iron core).

 

DJM saying it uses coreless is like Hornby saying it uses an iron core. It does not tell me anything about the motor performance. Unless I open the motor up, I have no idea if DJMs are skew wound or not, 5 poles or more or less or whatever. To be honest knowing such information will not tell me whether or not the loco will be a good/bad or indifferent runner nor how powerful the model will be. All we know is that the model may not be liked by certain controllers (and possibly DCC chips) - if your previous DJMs were ok, these will be too.

 

You can have an excellent coreless or a cheap and nasty one, just as you can with an Ironcore. For example, on the P2/Duke Hornby replaced their expensive £15 skew wound purposely designed model railway Iron core motor with a cheap off the shelf £1.50 3 pole one. I have both, the Duke seems to have got one from a better batch and runs really well - almost as good as 5-poles, the P2 won't move off until a certain voltage is reached but can be made to slow down after (under DCC this problem disappears). With Cheap motors, it is a lottery, some in the batch will be excellent, others dreadful as QC will have wider constraints and fewer rejects.

 

My two J94s have sufficient haulage power and runs really slowly. But the chassis is really rigid, it does not like some set track points in the doc areas (the layout is 10+ years old and suffers from creep). The USA tanks (3 locos), KernowDJM Well tanks (2 locos) and Kernow DJM O2s (2 locos) are not as rigid and are overall more agile and better runners.

Edited September 29, 2017 by JSpencer

[No Decorum]

JSpencer, I agree with all of that. Jointed coupling rods are generally a good thing because they allow more flexibility. However, I checked pictures of the DJModels Austerities very carefully to make sure that the rods were not jointed. If they had been, I thought that they would probably assume the odd angles of the ones on the O2 and 0-4-2T and given them a miss. My layout is perhaps three times older than yours or more and has developed kinks and dips. However, the curves are very gentle and none of my Austerities has derailed.

[JSpencer]

JSpencer, I agree with all of that. Jointed coupling rods are generally a good thing because they allow more flexibility. However, I checked pictures of the DJModels Austerities very carefully to make sure that the rods were not jointed. If they had been, I thought that they would probably assume the odd angles of the ones on the O2 and 0-4-2T and given them a miss. My layout is perhaps three times older than yours or more and has developed kinks and dips. However, the curves are very gentle and none of my Austerities has derailed.

 

On gentle curves the J94s are fine. No problem on the mainline at all. Oddly the DJM 71 suffers on certain spots on the mainline (the board joints are tops of the dips - I'm gradually reworking the track bed to make it less like a roller coaster) but copes well with the tight set track dock areas! So for now I have a 71 shunting in the docks and a J94 pulling the Golden Arrow ;-))

[New Haven Neil]

 ...again.I will be very interested in your comments on the running of your Class 71,Neil. Mine will move splendidly at slow speed,even with a load of 8 lit Hornby Pullmans +baggage van.......but runs out of clout as I increase power and even on max.current  (dc analogue) cannot reach acceptable scale speed above 45-50 mph.Others I have spoken with report the same. I am certainly no expert with regard to motors but I would hazard a guess that the installed unit is simply insufficiently powerful for the job.

 

My only other experience with coreless motors is with Faulhaber motors (quite small) installed in a coupe of Trix units ..Spanish Brotli Bahn being one.No problem there.

 

I have on order a Kernow DJM D6XX Warship. I have spoken with Chris Trerise ( I have posted on this elsewhere) with regard to my experience with the 71.He assures me that he will test it under load before release.

I certainly would not write off coreless motors but would ask.....Which coreless motor is appropriate for the model it is to be installed in ? Put another way...is it up to the job?

 

OK< I have been out to the garage and fitted a decoder to it!

 

It runs very well, fantastic slow speed control in fact but with a restricted top speed as far as I can tell -- I have an end-to-end layout.  I'd say it's not the lack of power, but the gearing that is the issue - maybe these motors have a lower rev ceiling so the gearing has been calculated wrongly.  My US diesels don't go much faster though - different market, different tastes?  Of course if it did 120 we'd all moan about that too  .  It's fine for my purposes, but I can see your point if you have a roundy-roundy that allows Tony Wright ECML speeds!  Not my thing, but if it is yours then point accepted. 

 

I actually wanted a 1366 but was unimpressed with the number of non or poor runners complained about, so thought a 1361 may suffice - but which?  Still not sure.....but I'm leaning Cornish-wards. The Mrs is from Looe.....