Rolling abilities, traction tyres & Mechanisms on 16.5mm track

[Allegheny1600]

Hi All,

After a brief discussion with David (Pacific231G) on "Wright writes", I wondered about the rolling stock "rollability", the use of traction tyres or not and qualities of mechanisms and I thought it may warrant a new topic of its own. I suspect such things have been discussed before but in disparate places?

 

Anyway, in the USA and the UK, the use of traction tyres has fallen out of favour but remains strong in Europe. About two or three years ago, Brawa released a class 245 diesel loco without traction tyres, my friend James bought one but it had to go back as it was 'gutless' despite being quite heavy, it could not pull very much at all up our then fairly fierce grades.

I am sure a similarly weighted American loco would have had more guts but I had nothing at the time available to compare.

 

Coincidentally, Brawa and Life-Like (Proto 2000, now Walthers) certainly used to share common components in their mechanisms, as did Hornby diesels of class 31, 56 and 60 era. I'm pretty sure the wheelsets would all be of the American RP25 type so other than all-up weight, why the difference?

 

Also, I find that modern rolling stock from most current manufacturers is very free rolling however what beats a long rake of Roco coaches for their free rolling ability? Very little in my experience.

 

Finally, other than Brawa, P2K and Hornby, how do you find current manufacturers mechanisms? I know that the current industry standard of a central motor, usually with flywheels, all wheel pick-up and drive pretty much originated with the Athearn 'Blue Box' mechanism, back in the early 1980s but things have come a long way since then.

Kato and Roco are still pretty much the gold standard for me but I found that Scale Trains(dot com) easily equalled Kato and ESU are arguably even better than Roco - what do you find?

 

Note: The mechanical part of my discussion is all based on diesel locos but I'm happy to include steam and electric outline.

 

Cheers,

John.

[34theletterbetweenB&D]

Traction.

 

Adhesion for traction in a traction tyre free world. It's weight on the driven wheelsets and the coefficient of friction between the tyre material and the rail that are fundamental. (Drag from unpowered wheels - if present - subtracts from available traction.)

 

Centre motor both bogies driven models will outperform an all wheels driven rigid chassis of the same weight for traction, most noticeably on curves and gradient transitions or uneven track.

 

Coefficients of friction for driven wheel tyre materials on nickel silver track; of three current RTR OO suppliers, Heljan probably marginally better than Hornby which in turn are about 6% better than Bachmann. (No great precision in these estimates.)

 

Drive lines in current RTR OO designs whether steam or D&E types are generally competent to fully exploit the adhesion available, with smooth running to avoid initiating slipping, and enough torque that the wheels will continue turning if the model is held back. It's all good proven technique developed for HO.

 

Free rolling.

 

Best current RTR OO products for this that I have encountered are the Bachmann coaches with (split axle) pinpoints running in formed dimples in phosphor bronze sheet (for the purpose of no incremental friction track power collection). These will roll away from rest on a true 1 in 200 once polished up from a few hours running time.

 

Regular metal pinpoints in plastic polish up with running and will consistently roll away from rest on a 1 in 100 or shallower, after a few hours running time. (That said, the best plastic bogie material that I have seen in RTR OO was from UK Trix circa 1970, matches the 1 in 200 rollaway from rest, negligible wear after many years use.)

[BoD]

Rolling ability.

 

The opposite of free rolling, I have some of the Horny turquoise OTA timber wagons where the axles sit in an upturned u shaped slot.  A rake of just six are very difficult to move.  What a drag, literally and figuratively speaking.

[steve1]

4 hours ago, BoD said:

Rolling ability.

 

The opposite of free rolling, I have some of the Horny turquoise OTA timber wagons where the axles sit in an upturned u shaped slot.  A rake of just six are very difficult to move.  What a drag, literally and figuratively speaking.

 

This is the tool you need. I've had one for years and it is invaluable.

 

https://www.micromark.com/HO-Truck-Tuner_2

 

Works just as well for OO!

 

steve

Edited October 30, 2019 by steve1
Extra info

[BoD]

20 hours ago, steve1 said:

 

This is the tool you need. I've had one for years and it is invaluable.

 

https://www.micromark.com/HO-Truck-Tuner_2

 

Works just as well for OO!

 

steve

 

 

Thanks for that Steve but the whole design is, in my opinion, quite primitive and its not surprising that they are not good runners.

 

There are no pinpoint bearings so your tool won't help.

The axles drop into the u shaped grooves and the plastic shape clips over to hold them in place.

 

Edited October 31, 2019 by BoD
duplicate word

[BoD]

Sorry to have hijacked your topic John.

I’m sure there are many others with thoughts on mechanisms, traction and free (or otherwise) rolling.

[The Johnster]

8 hours ago, BoD said:

 

 

Thanks for that Steve but the whole design is, in my opinion, quite primitive and its not surprising that they are not good runners.

 

There are no pinpoint bearings so your tool won't help.

The axles drop into the u shaped grooves and the plastic shape clips over to hold them in place.

 

Ugh.  That’s ‘orrible!  I cannot fathom the thinking behind such a device, or the solid mounting of the NEM pocket, which destroys the flex needed for the coupling’s correct operation. 

 

I doubt I can add much new, or of value for that matter, to Allegheny John’s general debate, most aspects of which have been extensively covered elsewhere, but FWIW here’s my two penn’orth anyway. 

 

My opinion of traction tyres is that there is nothing good and plenty bad about them.  They wear, stretch, cause derailments when they snap, interfere with pickup, spread crud all over your layout, and modern motors are by and large grunty enough to haul most trains without them (though I accept that for layouts like LB where 14 coach trains need to be hauled at scale 90+mph kit locos usually have the edge, and that most RTR benefits from whatever extra ballast you can get in). 

 

My opinion of plastic wheels on rolling stock is similar; they spread crud everywhere and induce drag at the axle points and the tyre/rail interface.  It’s spoiling the ship for a ha’porth of tar; this post is leaning towards old money references... Best performance is had from metal wheels with pinpoint axle ends, which work fine in plastic or nylon cone bearings but need brass top hat cone bearings in some soft plastic and whitemetal castings. 

 

So far as mechanisms go, I model British outline steam era and regard Bachmann as the definitive RTR performers.  These, and AFAIK all Btitish outline RTR steam locos, employ can motors driving through worm and cog gears. The most important performance parameters to me are good slow running and smooth stopping and starting, and I am happy with the performance these deliver.  Flywheels are good ballast but have little other value as their benefits are most needed at low speed, when their mechanical effect is negligible. 

 

But I contend that there is room for further improvement and that this can most easily be achieved by higher gear ratios; I’d like to see 30:1 for express passenger, 40:1 for mixed traffic, 50:1 for freight and shunting engines, and 60:1 for industrials, the aim being to enhance slow running and overall smoothness in starts and stops, and in speed changes.  

Edited November 1, 2019 by The Johnster

[BoD]

6 hours ago, The Johnster said:

Ugh.  That’s ‘orrible!  I cannot fathom the thinking behind such a device, or the solid mounting of the NEM pocket, which destroys the flex needed for the coupling’s correct operation. 

 

There is some flex. The whole plastic block supporting the axle can rotate although the springs are correctly fixed to the solebar. The lighter green plastic rod provides some springing to return it to the straight. I suspect it’s a design feature to cope with ‘train set’ curves but as you suggest, probably not their finest hour.

[34theletterbetweenB&D]

11 hours ago, The Johnster said:

...So far as mechanisms go, I model British outline steam era and regard Bachmann as the definitive RTR performers.  These, and AFAIK all Btitish outline RTR steam locos, employ can motors driving through worm and cog gears.

This appraisal is probably dependent on your area of interest and thus the models you have sampled.

 

Bachmann for sure set a new standard in RTR OO twenty years ago with their WD 2-8-0, and for my money haven't since improved from that high point. At introduction that had a five pole Buhler motor, 40:1 reduction, efficient pick up on all driven wheels, two driven axles sprung, either side of the gear axle. Plenty of good introductions then followed, and the most recent for my interest the Ivatt C1 large atlantic is very impressive for tractive performance; quiet and smooth up to full express speed and good traction. (Sadly the once ubiquitous sprung driven axle has disappeared from their more recent introductions, its last appearance was I believe on the A2 pacific introduction; and five pole motors are gone replaced by their very efficient 3 pole types. Happily DCC completely masks the motor change.)

 

Hornby closed the gap after departure from Sanda Kan and once the design clever episode was behind them. Really neat productions such as the B1, B12, B17, D16, J15, J50, K1, L1 and O1 have five pole skew wound motors, efficient short profiled pick up wipers in the style long used by Bachmann, and good reduction ratio choices for a little over maximum scale speed at 12V. Furthermore attention has been paid to obtaining sufficient weight well centred within the coupled wheelbase, latterly by use of largely metal bodies. No sprung driven axles, but otherwise very good, quiet and smooth from dead slow and with good traction.

 

Heljan. I have their O2 2-8-0's. The mechanism constructional scheme is a pain, and I haven't had one apart, (and hope never to have to!). But no complaints about performance, quiet and smooth from dead slow, pulls like a hero thanks to an appropriate reduction ratio (unknown) and plentiful weight. Fine feature, the use of a much smaller flange depth than normal in OO RTR, with no impact on track holding despite the coupled chassis being rigid (30" minimum radius layout) and the resulting considerable benefit in appearance.

 

Oxford Rail. New kid on the block, and their N7 0-6-2T is the business. Conventional construction, there's some compensation in the driven wheelsets, a good motor and drive line, efficient pick ups, and plentiful weight yields enough traction for 8F turns. OK, has yet to put in several years reliable service, but the signs are good, and the construction makes it eminently maintainable and repairable. Hopefully OR are on a solid footing from now on. (Repeat in this style on the J27 and they will have a winner.)

 

Dapol, Hattons, etc.. Get with the programme, make something LNER/ER for me to play with.

 

 

[John Tomlinson]

On 30/10/2019 at 20:03, steve1 said:

 

This is the tool you need. I've had one for years and it is invaluable.

 

https://www.micromark.com/HO-Truck-Tuner_2

 

Works just as well for OO!

 

steve

Bill Bedford marketed a tool with similar purpose some years ago, I don't know if he still does.

 

In his case however the tool bored a hole that would take brass bearing cups - like you'd find in a wagon kit - the outcome however was the same, a great improvement in free running.

 

John.

[The Johnster]

3 hours ago, 34theletterbetweenB&D said:

This appraisal is probably dependent on your area of interest and thus the models you have sampled.

 

Bachmann for sure set a new standard in RTR OO twenty years ago with their WD 2-8-0, and for my money haven't since improved from that high point. At introduction that had a five pole Buhler motor, 40:1 reduction, efficient pick up on all driven wheels, two driven axles sprung, either side of the gear axle. Plenty of good introductions then followed, and the most recent for my interest the Ivatt C1 large atlantic is very impressive for tractive performance; quiet and smooth up to full express speed and good traction. (Sadly the once ubiquitous sprung driven axle has disappeared from their more recent introductions, its last appearance was I believe on the A2 pacific introduction; and five pole motors are gone replaced by their very efficient 3 pole types. Happily DCC completely masks the motor change.)

 

Hornby closed the gap after departure from Sanda Kan and once the design clever episode was behind them. Really neat productions such as the B1, B12, B17, D16, J15, J50, K1, L1 and O1 have five pole skew wound motors, efficient short profiled pick up wipers in the style long used by Bachmann, and good reduction ratio choices for a little over maximum scale speed at 12V. Furthermore attention has been paid to obtaining sufficient weight well centred within the coupled wheelbase, latterly by use of largely metal bodies. No sprung driven axles, but otherwise very good, quiet and smooth from dead slow and with good traction.

 

Heljan. I have their O2 2-8-0's. The mechanism constructional scheme is a pain, and I haven't had one apart, (and hope never to have to!). But no complaints about performance, quiet and smooth from dead slow, pulls like a hero thanks to an appropriate reduction ratio (unknown) and plentiful weight. Fine feature, the use of a much smaller flange depth than normal in OO RTR, with no impact on track holding despite the coupled chassis being rigid (30" minimum radius layout) and the resulting considerable benefit in appearance.

 

Oxford Rail. New kid on the block, and their N7 0-6-2T is the business. Conventional construction, there's some compensation in the driven wheelsets, a good motor and drive line, efficient pick ups, and plentiful weight yields enough traction for 8F turns. OK, has yet to put in several years reliable service, but the signs are good, and the construction makes it eminently maintainable and repairable. Hopefully OR are on a solid footing from now on. (Repeat in this style on the J27 and they will have a winner.)

 

Dapol, Hattons, etc.. Get with the programme, make something LNER/ER for me to play with.

 

 

My area of interest is South Wales in the 1950s, which means a predominance of Baccy mechs underneath 57xx/8750 panniers, 56xx, and small prairies, plus a 57xx mech powering a ‘Limbach’ 94xx (due for replacement when the new 94xx arrives, and the mech already has a 57xx body to give it a new home).  There is a variation of performance among all these mechs, which all use identical motors, gears, and pickups, but even the worst still turns in an adequate performance.  

 

There are two Hornbys, a current tooling 42xx and a recent tooling 2721.  They are good performers, though a good bit of fiddling was needed to get the best out of the 2721.  They cannot match the Baccys though, being let down by the pickups IMHO.  The 2721 seems very sensitive to dirt, and requires frequent cleaning; the Baccys will run for a very long time before complaining, and a quick clean has them back on top of things.   

 

Future plans include a Southeastern kit chassis for a Wills 1854.  I will only have myself to blame if this does not run well... 

[melmerby]

3 hours ago, 34theletterbetweenB&D said:

This appraisal is probably dependent on your area of interest and thus the models you have sampled.

 

 the most recent for my interest the Ivatt C1 large atlantic is very impressive for tractive performance; quiet and smooth up to full express speed and good traction.

 

Oxford Rail. New kid on the block, and their N7 0-6-2T is the business. Conventional construction, there's some compensation in the driven wheelsets, a good motor and drive line,

 

 

And there is another side

Bachmann C1 Atlantic, mine is the worst performing Bachmann loco I have, it slips on the slightest slope, a 57XX Pannier will easily outperform it. My Bachmann 4-4-0 locos are better. IMHO it is too light.

Oxford, The Dean Goods is grossly underpowered with a puny 3 pole coreless motor and slows down noticeably when loaded, worse than any other loco I have, It just stops on a gradient with anything other than a light load, it doesn't slip.

[The Johnster]

Difficult to comment on haulage on a layout with 11 coal wagons and a van being the biggest load.  My 56xx and the Hornby 42xx handle the loaded coal train easily but the Limbach 94xx,  ballasted as heavily as I can manage, can be a bit lightfooted with them.  I suspect my 2721 could pull the planet out of orbit if I wanted.  

[melmerby]

7 hours ago, The Johnster said:

 The 2721 seems very sensitive to dirt, and requires frequent cleaning

Unless modern ones are improved it was actually only a 0-4-0 as the centre wheelset was undersize and didn't touch the rail.

[The Johnster]

Modern ones are slightly improved, and the wheels are now all the same size.  IIRC the initial release of this loco had a flangeless centre wheelset and the undersize version came along later.  My chassis has springing for the rear axle and hexagon nut headed crankpins.  But it's still an 0-4-0 in pickup terms as the centre wheelset has traction tyres (the first thing to be ditched on mine, even before I got her home from the shop).  

 

I've worked her up a bit; repaint, brass numberplates, crew, real coal, new buffers, chimney/dome/safety valve cover from a moribund Westward 64xx, but she'll never be a scale model of anything, and the crudeness of the skirts beneath the boiler is awful.  

Edited November 2, 2019 by The Johnster

[DCB]

I really hate traction tyres, they make the track filthy.    Apart from the seldom used T9 and schools, and a Triang 9f which is the only thing which can shift my oil tanks Traction tyres have been banned from the layout and this has slashed track cleaning quite dramatically.

The days when improved rollability was required are long gone. 20 years or so ago Mainline/ Bachmann introduced embarrassingly free running stock which runs away on the almost level.  Its ridiculous having to keep  your layout level better than 1 in 150.  They actually need brakes for realistic operation.

The weight, number of wheels touching the track, and wheel profile seem the critical factors.   Many new RTR UK outline steam  locos dramatically improve their haulage performance when run in, our Bachmann WD doubled its haulage power and now competently manages 4F turns even if it can't pull half what a Wrenn 8F does.   The Oxford Dean is hopeless for traction but runs beautifully and sooner or later it will have its DCC gubbins replaced with good old lead in the hope of getting decent traction or else its becoming a withdrawn static loco.  

The old standard Romford tyre profile and the Hornby Dublo pre Triang one seem to grip code 100 track better than the modern Hornby / Bachmann type.

However when dirty track is encountered axle loading is king.  The old 4 wheels on the track Triang 0-6-0 chassis with Romfords and  a die cast body will plough through filth and even standing water which stops lighter all wheel pickup locos dead on our outside branch.

 

[Philou]

Regarding traction tyres, I agree with the view of The Johnster regarding crud and the like. I retrieved a load of continental locos that my father had collected over the years - steam and D/E outline - from a number of continental manufacturers, the likes of Jouef, Piko, Fleischmann, Roco etc. ALL, yes ALL have a problem with saggy tyres that have become soft and loose due to oil getting onto them while being in store. Whilst the D/E locos will allow the tyre to slip off the wheelset, there is no way of removing the tyres from the steam locos without dismantling the coupling rods and valve gear - some being very intricate (think Walschaerts). Then there is the issue of finding spares as most of the locos are not current.

 

Tyres? No bl**dy thanks!!

 

Cheers,

 

Philip

[34theletterbetweenB&D]

18 hours ago, melmerby said:

And there is another side

Bachmann C1 Atlantic, mine is the worst performing Bachmann loco I have, it slips on the slightest slope, a 57XX Pannier will easily outperform it. My Bachmann 4-4-0 locos are better. IMHO it is too light...

(Check for drag on all the wheelsets and not too much spring pressure on the carrying wheels. Adding weight is always a good plan, paying attention to keeping the weight well centred in the coupled wheelbase, but I am sure you know all this.) I would fully expect a total adhesion 0-6-0T to easily outperform an atlantic model in traction. But with free running stock, once going the atlantic will take a typical train load up to a scale 90mph and - romance - it ain't a grubby little shunty tank up front, but one of the most beautiful types to run in the UK!.

 

Mine performs on the Queen of Scots with 8 of the K type all steel car models from Hornby, and will go up a long 1 in 80 with these taken at a run. It cannot restart if stopped on that gradient though, which an 0-6-0T would easily manage. The comparison I make is to my attempts in the long ago to make good running atlantics from whitemetal kits. This was purgatory, so difficult to make them pull as they should. To have a RTR OO model which does so well is marvellous.

 

18 hours ago, melmerby said:

And there is another side...

The Dean Goods is grossly underpowered with a puny 3 pole coreless motor and slows down noticeably when loaded, worse than any other loco I have, It just stops on a gradient with anything other than a light load, it doesn't slip.

I suspect a duff motor there. The N7 has a coreless motor in it, and visually compared to photos of the Dean goods innards (never seen this model in the flesh) it looks like the same unit. As this motor performs so well  in the N7 , it should do so elsewhere.

[melmerby]

2 hours ago, 34theletterbetweenB&D said:

I suspect a duff motor there. The N7 has a coreless motor in it, and visually compared to photos of the Dean goods innards (never seen this model in the flesh) it looks like the same unit. As this motor performs so well  in the N7 , it should do so elsewhere.

No. It's been replaced (due to failure), the original one was just the same. I have a second Dean Goods which is no different.

[34theletterbetweenB&D]

10 minutes ago, melmerby said:

No. It's been replaced (due to failure), the original one was just the same. I have a second Dean Goods which is no different.

That is disappointing. Cannot do it at the moment, but would it be useful to have the dimensions of the motor in the N7, can length and diameter, shaft diameter; just in case it is compatible? While about that l will get the gear ratio on the N7 too, something which I keep forgetting to assess...

[melmerby]

45 minutes ago, 34theletterbetweenB&D said:

That is disappointing. Cannot do it at the moment, but would it be useful to have the dimensions of the motor in the N7, can length and diameter, shaft diameter; just in case it is compatible? While about that l will get the gear ratio on the N7 too, something which I keep forgetting to assess...

Can diameter is about 10mm (circular) length about 20 mm, shaft 1.5mm.

I posted some picture in the Dean Goods topic.

The early one had a 5 (?) pole iron cored mmotor which was larger.

 

[34theletterbetweenB&D]

N7 motor: length 23mm over the can, diameter 10mm, shaft diameter 1mm.

Reduction ratio estimated at 48:1 (very fiddly).

 

No complaints about traction. During a careless moment with my first one on test I ran it into the back of a standing Heljan O2 at low speed, and it shoved it along.

 

Motor response very non linear, both examples, and this was immediately apparent during DC testing. The set up in DCC required CV6 at circa 130, CV5 at circa 160, to obtain 30mph at speed step 14, 60mph at speed step 28. (One has Lenz Standard, the other a Zimo MX600, and the CV values are very similar.) Both run smoothly and quietly from dead slow to the set maximum, most satisfactory.

[melmerby]

50 minutes ago, 34theletterbetweenB&D said:

N7 motor: length 23mm over the can, diameter 10mm, shaft diameter 1mm.

Reduction ratio estimated at 48:1 (very fiddly).

 

 

Checked mine again (I had the dud one sitting in front of me) and the dimensions are nearer to what you quote, the shaft is 1mm (not sure where 1.5mm came from)

 

It's probably similar to this:

https://www.alibaba.com/product-detail/Double-shaft-coreless-motor-CL-1021_60721787047.html?spm=a2700.7724857.normalList.7.478028b5VRDNlB&bypass=true