Kernow Adams O2

[51E]

Is that really the conclusion that is implied in this thread....that insufficient adhesion results from its design ? Surely not.When the Isle Of Wight versions arrive,more grunt will be needed to haul a prototypical rake than the Maunsell sets seen here for sure.And is there a substantial difference between analogue and DCC.in haulage capability with the O2 ?

If you read the post that I quoted it says " the designers have needed to find space for a DCC decoder and small speaker". I was merely saying that the case for more weight is greater than the need for a small speaker if people are having trouble with 02's only being able to handle a couple of coaches.

Personally yes I would say its down to the designers to get it right. No one should have to be fitting their own weight. As pointed out by someone else, the Hornby M7 had a similar problem so the 02 isn't alone.

Even you point out more grunt will be needed for the Isle Of Wight locos and at the minute a few 02 models seem to be struggling with only a couple of coaches.  

[billbedford]

Yes. Too much plastic and not enough mazak. Other manufacturers are using mazak running plates and other components to get adhesive weight up, and have been for some time. Am I right in guessing that the O2 is mostly plastic apart from the chassis block ?

 

You are not right, in fact the designer couldn't really get much more muzak into the space he had to work with 

[Dunsignalling]

As with all new locos, they should pull a lot better once the shine has been worn off the driving wheels and all the other moving parts have had the chance to bed in properly.

 

My smaller Bachmann locos (e.g. 2251s and Ns) could only handle 3 or 4 coaches without slipping after the recommended hour of running in (on a rolling road).

 

Now they have done 2 or 3 hours of actual work, and the wheels have been cleaned a few times, they can manage twice as much. 

 

John

Edited November 13, 2015 by Dunsignalling

[PhilH]

You are not right, in fact the designer couldn't really get much more muzak into the space he had to work with 

Give it a year or two and we'll all be bemoaning the use of so much mazak when it starts to 'fatigue'...

[Bill]

Purley Oaks, on 13 Nov 2015 - 08:57, said:

No please don't, the pics are great!

 

Hopefully Dave Jones will respond at some stage - but I still applaud him and Kernow for making such a wonderful model.

 

Magnahesion anyone?

 

Mal

I don't think he can respond, as much as he might want to.

As supplier to Kernow of the O2s they are marketed under Kernow's brand.

He would probably be interfering and in breach of who knows what arcane contract laws.

But Kernow probably could.. .

Then

Then instead of magnahesion here is a really, really bad idea for someone to shoot down - get a Hornby 2 BIL and re-body it to suit as a banker???

(Or stick a black beetle under a standard coach?)

Edited November 13, 2015 by Bill

[Butler Henderson]

Given that the track and test conditions are the same for both locos and that 30225 now has a modest additional weight over the front drivers I am now more puzzled than ever as to why one loco runs better than the other.  Items yet to be checked include back-to-backs and pick-ups so either or could be part or all of the issue here.

Have you retried 30225 without the added weight?

How much weight have you added - presumably the point can be reached where too much weight will act like someone holding the loco down.

[Wheatley]

You are not right, in fact the designer couldn't really get much more muzak into the space he had to work with 

Maybe not inside but almost every Bachmann loco I own has a cast footplate. Does the O2 ? I'm aware there are balance issues with 0-4-4s, I own a couple of whitemetal ones, but balancing for optimum traction is easier if there is weight there in the first place.

[Dunsignalling]

Maybe not inside but almost every Bachmann loco I own has a cast footplate. Does the O2 ? I'm aware there are balance issues with 0-4-4s, I own a couple of whitemetal ones, but balancing for optimum traction is easier if there is weight there in the first place.

The problem with putting a cast running plate on a 0-4-4T is that the portion over the driving wheels will be beneficial and the other half will be counter-productive. That is the Achilles Heel of most kit-built ones; a Wills/SEF G6 0-6-0T will pull twice as much as an almost identical O2 0-4-4T from the same maker, just through having all the weight available for adhesion and none detracting from it.

 

The ideal model 0-4-4T would have a heavy (cast metal) front half with the rest made from lightweight materials. The challenge would be hiding the join and avoiding difficulties arising from differing expansion rates in each half. Alternatively, you could go the whole hog and make the chassis as an articulated unit rather than following prototype practice. An article by a Mr. F. Coulton in the Railway Modeller as long ago as February 1967, describes what I think is the best solution.

 

Although I haven't yet molested 30182 or 30193, I anticipate ripping the DCC gubbins out of the smokebox and filling it with a roll of lead flashing where it'll do most good. If I want to fit a chip (which I don't, at present) it will just have to go somewhere else (probably in the bottom of the cab, hidden by a false floor and a sawn-off crew).

 

I am afraid that, if you want DCC and sound and a fully visible cab interior in a diminutive 0-4-4T, it will inevitably compromise pulling power to some degree. On a branch line layout with no hills and 2-or 3-coach trains, it won't be a problem. If you want all those things but also want to run longer trains or tackle tough gradients, adding a powered bogie to one of the coaches (or the loco itself) is the obvious answer. 

 

John

Edited November 13, 2015 by Dunsignalling

[Gwiwer]

Have you retried 30225 without the added weight?

How much weight have you added - presumably the point can be reached where too much weight will act like someone holding the loco down.

 

It's about 10 grams and the loco performance hasn't really changed much at all.  I suspect, given that 30182 performs well, that something else and not weight or balance is the cause.  I may be able to have the back-to-backs checked today and can readily ease out the pony-truck contacts to reduce drag there.

[SRman]

No please don't, the pics are great!

 

Hopefully Dave Jones will respond at some stage - but I still applaud him and Kernow for making such a wonderful model.

 

Magnahesion anyone?

 

Mal

Thanks Mal.

 

Just for that, here's one more!

 

This time it is with the front coupler and pocket removed, and all the brake pipes and dummy screw coupling fitted. There was some digging through online photos to find out what pipes to fit and where they went, and a considerable amount of swearing, retrieving dropped pipes, pulling them off the forceps when they glued to those instead of the buffer beam, discovering I've fitted the thicker pipe in the wrong place (it is the one now correctly nearest the right-hand buffer, as you look towards the loco), etc., etc.!

 

I intend this locomotive to be mainly for Pull-Push working, so thought it worthwhile to detail up the front as much as possible, something I also did to a Hornby BR M7 0-4-4T 30108 a while back, for the same reasons.

 

It is not practical to add all the buffer beam pipework to the rear of the loco as they would interfere with the bogie swing.

 

 

 

Next up will be to weather the pipework on the whole locomotive, and later on, weather more of the loco itself. Beautiful as those brass/copper pipes are, they are too clean and obvious for what I want on what is to represent a hard-worked example of the class.

Edited November 14, 2015 by SRman

[Gwiwer]

Good work there Jeff.  I ended up with couplers on both ends of each of mine as they will have to run in both directions.  Even the push-pull fitted 30182 will sooner or later have to couple to something at either end.  The IoW one will be more of a static display piece and will have full plumbing fitted at one end.

 

30225 visited Llanbourne today which is the location of the nearest available back-to-back gauge.  The leading drivers were found to be wider than everything else by half the width of a gentleman gnat's pride and have been squeezed closer together.  She now runs as well as 30182 and I consider the issues dealt with and so far as my locos go the problems are solved.

[ChrisG]

It is possible that I have missed previous discussion on this particular topic, so my apologies if in fact it has been well-aired.... but no-one seems to be making very much of the fact that the O2's drivers are driven by a geared transmission. I had a couple of them (owned by a friend) trundling very sweetly around my layout, all as steady as a rock and ultra-responsive, straight out of the box. At this point I didn't know there was anything remarkable about the mechanism. Then I read that it was geared and the connecting rods were effectively cosmetic.  

 

Surely this is revolutionary for a UK steam outline model in OO? And it is surely the way that UK RTR OO needs to go?  

 

I have only had RTR locos on my IOW layout since suitable prototypes came to be available (a Bachmann E4 was the first, although I have had a Bachmann 08 shunter for some months now for testing newly built track). The 08 was my yardstick until now, and I have to say the O2, on first outing, has put it in the shade. Leaving aside any problems there may be with the weighting, I am very happy that the first IOW RTR loco in OO seems to be about the best that has ever been produced. 

 

Chris

[billbedford]

Surely this is revolutionary for a UK steam outline model in OO? And it is surely the way that UK RTR OO needs to go?  

 

 

 

The Bachmann 4-4-0s have a similar arrangement, as has the Beattie well tank.

[billbedford]

The problem with putting a cast running plate on a 0-4-4T is that the portion over the driving wheels will be beneficial and the other half will be counter-productive. That is the Achilles Heel of most kit-built ones; a Wills/SEF G6 0-6-0T will pull twice as much as an almost identical O2 0-4-4T from the same maker, just through having all the weight available for adhesion and none detracting from it.

 

 

Isn't that to be expected? The full size O2s had just about 2/3 the adhesive weight of the G6s and I have believe that that ratio could be a a lot worse on a model, especially if it was built without compensation or springing.

[phil-b259]

 

 

 

Next up will be to weather the pipework on the whole locomotive, and later on, weather more of the loco itself. Beautiful as those brass/copper pipes are, they are too clean and obvious for what I want on what is to represent a hard-worked example of the class.

 

You might also wish to do something about the end of the vac pipe stick out in your photo. While it doesn't look too bad with coaches (or another loco) coupled next to it, such pipes would in reality have to be correctly stowed on the 'plug' (which is moulded onto the vac pipe assembly)  if not being used or otherwise the loco would never have been able to generate enough vacuum to release the train brakes.

 

I solved the issue by a small dab of superglue gel and pushing the free end of the pipe back and sticking it to the vertical bit next to the bufferbeam.

[Oldddudders]

You might also wish to do something about the end of the vac pipe stick out in your photo. While it doesn't look too bad with coaches (or another loco) coupled next to it, such pipes would in reality have to be correctly stowed on the 'plug' (which is moulded onto the vac pipe assembly)  if not being used or otherwise the loco would never have been able to generate enough vacuum to release the train brakes.

 

I solved the issue by a small dab of superglue gel and pushing the free end of the pipe back and sticking it to the vertical bit next to the bufferbeam.

Good point. ISTR the 'plug' being called a 'dummy'.

[Wheatley]

The problem with putting a cast running plate on a 0-4-4T is that the portion over the driving wheels will be beneficial and the other half will be counter-productive.

So make the boiler and smokebox out of Mazak then. The problem isn't insurmountable.

[Oldddudders]

The problem isn't insurmountable.

Good. In the meantime I'll happily make do with the Kernow version.

[Brian Kirby]

The proof that 0-4-4Ts in particular, require compensation around the driving wheels, is slowly rising to the surface. Now we are reading all the stories of woe about poor pulling power, next it will be wheels getting dirty and poor electrical pick-up. With four rigid-mounted driving wheels and a long rear overhang, everything now pivots (or rocks) on the inner driving axle, just like on the Hornby M7 (of which many have been privately side-lined with dirty wheels.). On a rigid set-up, the seating of the driving wheels on the track depends on the calibration of the rear bogie spring, if the spring is too weak, the loco will sag at the back and the front drivers will lift off the track (the see-saw effect). If the bogie spring is too strong, it will raise the back end of the loco and lift the inner drivers off the track, the forward weight now transferring to the front drivers. The trouble is, you can never get the bogie spring at the perfect pitch, unless your track and layout is like the proverbial billiard table.

     Any adding of weight here, and tweaking there, is really just fudging around the issue, those driving axles need to rock, so they can achieve self-levelling, then ALL the wheels will happily press down on the track with improved weight distribution. There is another, less effective method, you introduce a degree of vertical slop to the front axle bearings, with preferrably a spring pushing down on the front axle, this will counter the rocking see-saw effect, but is not a perfect solution, and we don't want a bouncy castle. I have been tempted to try this on one of my several Hornby M7s, i haven't the time to build new chassis for them all, but it should improve matters. Despite the snags, i still intend to buy a second lovely O2, they really are a thing of beauty (and a joy for ever whilst stationary) and so smooth and quiet, with a bit of front axle slop they should pull more and pick-up better.      

                                                       Cheers, Brian.

Edited November 14, 2015 by Brian Kirby

[roundhouse]

My O2 is know out of the box. Back to backs checked and Fi e. It's had a little jaunt on the layout but now running in on the rolling road with a Bachmann6 pin decoder fitted

[2ManySpams]

Last year I bought a 7mm / O Gauge kit of an O2 from Jim of Connoisseur Models. I love the O2 as a prototype, a useful small loco and perfect for my Bodmin based layout. Being a kit building novice I'd not really given the wheel arrangement much thought but by talking to folk on here and reading around I soon realised that i'd picked one of the most difficult wheel arrangements to get running and pulling well. Typical.

 

My model has the drivers articulated in compensation beams and the rear bogie sides can also twist. What I've built isn't far off a twin axle bogie diesel. It does however stick to the track like glue.

 

The next problem was balance. I needed to get the center of gravity in between the driving wheels to maximise pulling power. Considering how far forward the driving wheels are, and how far rearward the available volume in the body for ballast is, this is far from easy. I found it very difficult in 7mm, so hats off to Kernow for getting something that runs.

 

It does seem to me that there are a lot of armchair critics in this thread who are lambasting Kernow for heinous mistakes and the O2s inability to pull massive expresses. With the best will in the world a 4mm RTR model made to a reasonably low price in a mass production facility is always likely to struggle.

 

Not happy with the pulling power of the Kernow model? There's always the option of building your own greatly superior version. Having a go would show you just how difficult getting the weighting and articulation is in such an unbalanced and small bodied loco.

 

Be sure to report back how you've got on.

[Brian Kirby]

Well i'm not bashing Kernow, as i said at the Brighton Conference (to paraphrase Harold Wilson), i think they've made a splendid effort dealing with a difficult wheel arrangement. It was probably too much to expect a RTR compensated chassis, the costs would no doubt of shot up, what they have provided is a fair compromise (IMHO). i just hope i can offer a few ideas to improve running and pulling power.   BK

[Dunsignalling]

Isn't that to be expected? The full size O2s had just about 2/3 the adhesive weight of the G6s and I have believe that that ratio could be a a lot worse on a model, especially if it was built without compensation or springing.

Indeed, but the main thrust of that sentence was that just adding a cast running plate to a model 0-4-4T might do as much harm as good. The critical aim is to increase the weight over both sets of driving wheels without adding any further aft where it tends to reduce adhesion on the leading pair.

 

John

[Dunsignalling]

So make the boiler and smokebox out of Mazak then. The problem isn't insurmountable.

Yes, but NOT the running plate which would just distribute extra weight along the entire length of the loco and achieve nothing.

 

John

[Brian Kirby]

So make the boiler and smokebox out of Mazak then. The problem isn't insurmountable.

Have you made a start on this yet? Will we see it before Christmas? ( And don't forget to do some pics)   BK

Edited November 14, 2015 by Brian Kirby