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Hi All I am new to model railways.Could someone tell me the difference between steel track and nickel and which is better? Anty
 

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Hi Anty, welcome to the forum. The difference is the colour, steel being bright silver when new & nickel having a slight yellowish tinge to it. Not sure if you can get steel track anymore as the main producers ( Hornby/ Peco) make it in nickel silver as do kit & rail parts suppliers like SMP so that kinda answers your " which is best", although I suspect that some modellers will prefer steel.
 

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Hi There.
One other difference is that steel will rust in damp conditions where Nickel will not. I also believe that Nickel is easier to bend than steel.
 

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C&L Finescale...famed for producing trackage for EM and P4 as well as OO

http://www.finescale.org.uk/show_page.php?...1535d9320651b#g

produce their rail in steel as well as N/Silver.

true, steel rail WILL rust in damp condiditons.....I would question whether it's wise to have a model railway in'damp' environment...unless deliberately building outdoors?

However, nickel silver rail also has a 'corrosion' issue..or rather, a tarnishing issue....which is about the same thing, I think.

I prefer steel..if track building.....some say steel rail allows for better adhesion? I have little evidence to support or deny this....since my layouts tend to be of the shunterupper type......I don't get much joy out of going large.

There may also be issues regarding soldering........some say N/S is easier to solder with?

Currently, N/S is cheaper as a raw material than steel, so I believe.

N/S curves easier than steel...steel retains its shape better.......and I do wonder whether all the makers get their rail from the same factory?

SMP also offered phosphor-bronze rail.....doubtless excellent for electrical conductivity, plus it's ready-weathered.

However, if the OP is looking at some cheapo flex track, which may be steel, well, ,.....................it wont be a bad deal.......

One trick the US modellers used [whether on steel or N/S I never ascertained] was to coat the rail in Wahl Clipper oil...applied sparingly of course........amongst other things they reckoned it kept wheels and railheads cleaner.....
 

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Just another modeller
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****

NS oxidises quite badly - I had the black stuff that rubs off analysed by a university and it is 95% copper oxide - a great insulator... so you could say that it "rusts" too - but almost invisibly :).

Only NS is used by all the major RTR track people. Silly really.

The problem is most Mfrs use too little Nickel in the mix (less than 17~18%) so its not a good material for rail really - if they used 24% nickel then it would not corrode nearly as much. (Coin grade NS is 25% from memory)

Phosphor bronze never loks realistic even if painted as the railhead is never silvery as it should be on well used track.- and it oxidises worse than NS. to be avoided.

Steel is fine in the average layout environment but as a rule of thumb not in anywhere that gets extremes of temp and humidity as dew point means moisture = surface rust unless treated.

steel files and bends at least as easily as NS and is quite easy to solder as well. In bullhead rail its a super material to work with for hand made pointwork...

C&L do code 82 flatbottom rail and BS95R bulhead is an excellent high nickel version of NS that almost looks like steel - they also do steel rail in both.

Its not logical that NS is the metal used really.... NS is very slippery as an alloy! A loco will pull up to 25% more on steel track. A well chosen grade of stainless steel would be the best answer - none of the down sides of NS and all the benfits of steel.

Anyway... look for a brand that looks less "yellow" the yellower, the less NS is in it. Tilling is a better choice therefore than Peco!
 

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Gaugemaster still sell a steel flexi-track and a number of other model shops stock it. Best used in dry conditions ie a spare room rather than an unheated shed or garage. Some older locos have 'magnadhesion' which needs steel track and provides superb traction. It is made in Italy and always used to be a lot cheaper than nickle-silver.

Regards

David Y
 

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steel track in a dampish atmosphere shouldn't be a worry.....most of it will be under a coat of paint..if not, don't worry...the top surface will stay clean with use, especially if a wee drop of machine oil is smeared on now and then.......and if used infrequently, then track cleaning is the way of things...but N/Silver has the same issues...lack of use means time for the track rubber?
 

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Paul Hamilton aka "Lancashire Fusilier"
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Interesting to look at the relative coefficients of friction for the various materials. It should be noted however that this is when the surfaces of the parent metal (including the wheels) are spotlessly clean, otherwise ,aside from the electrical conductivity issues mentioned above, the friction and thus efficiency of converting the motor power into motion is really about the tarnish or oxidising films' friction coefficient. For instance static friction coefficient for steel is around 0.75 and this reduces to around 0.25 when a thick film of oxidation is present (this is a steel on steel case)
 

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***True, but NS is like its been soaped compared to steel :). and NS wheels on NS track is so slippery I still can't figure how the brands got it so wrong when it came to choosing what to use.

Here's one for you Paul - and all other engineers on MRF.

I am researching a future project and as part of it, I was interested in the huge reputation of the Portescap motor/gearbox combo sold in UK. Its a very good product that has become very, very expensive, but there is no denying its real world performance

Frankly in most repects the Escap RG4 and RG7 are nothing special as motors go and compared to may Iron core motors, quite wimpy power wise in fact... Anyway - as an offshoot of this overall motor/gearbox related project, I recently received some learned analysis of model railway gearboxes by an august figure in mechanical engineering.

Best efficiency in ANY worm drive gearbox, in any brand, in any ratio, coupled to any motor (motor to wheels power transfer) was 18%. That means less than 20% of the real motor power actually gets to the wheels.

Conversely, using various bevel gears to transfer the power from motor to axle resulted in an always better than 40% efficiency - a really huge practical difference, which explains quite handily why the portescap gets good results from a less than average power coreless motor.

Why is it so extreme?

I accept the numbers, but am still amazed by the huge losses in worm drives. They always appear smooth and well meshed... so...

"why is it so?"

Regards

Richard
 

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Subjectively *, the very lossy nature of worm drives is a function of the power transfer by a sliding contact of the working surfaces. Spur gears can be made pretty efficient with tooth profiles optimised so that the working surfaces have a line contact which rolls across the tooth face, there is prac tically no sliding action at all. Which is fine when the drive axis stays parallel, but when there is a requirement to turn the axis of a drive line, it is no longer possible to maintain a rolling line contact. It is a shame that bevel gearing is more expensive than worm drive, otherwise this more efficient option for our frequent need to turn the drive in railway modelling might be more widely available.

* I once had the great privilege of working with a team of people who engineer serious geared transmissions. (Think as big as your house, for electrical power generation.) When they started into the arcana of their speciality, my head very quickly began to hurt!
 

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as a non-engineer.......the above perhaps explains why the ring-field motors, and other 'pancake'-style motors were so popular with makers in the past?

less efficiency losses?

On the basis that motorcar makers were not eedyuts.....the spiral bevel gears of a final drive [rear axle, or transaxle] must be efficient at transmitting power?
Therefore,surely not beyond the wit of model engineers to produce a spiral bevel gearbox?

another one.....Rivarossi, with their ancient steam locos, used a very hefty motor....and an equally hefty worm gear.....the diameter of which was considerably larger than those used by the more common makers.....was there a secret advantage in using such a large diameter worm? [with, I believe, a matching concave pinion..or is it worm, with pinion on motor shaft??]

what are the losses from belt , or chain drive?

{to turn drive through 90 degrees?]
 

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A toothed belt or 'bicycle' style linked chain is pretty efficient (you would die on a bicycle were it not so!), and the losses in using such a drive to turn the drive axis are small. However, wear on the belt or chain is significant.

When the basics of the motor car were still being developed there was much experimentation to find the best trade off between efficiency losses and manufacturing cost in the gear arrangement to turn the propshaft drive onto the back axle. Forms of worm drives were tried, but it quickly became apparent that the relatively high cost of machining curved face bevel gears paid off in getting a greater proportion of engine output to the road wheels. I suspect for model railway products the increment for a more powerful motor to offset the losses caused by simply machined but inefficient gearing, is smaller than the increment for gears which present a more exacting machining task.

A 'fat' worm doubles up as a flywheel, Bachmann still make some use of this in their models. To be effective the flywheel should be as large a diameter as possible, to maximise kinetic energy storage, which increases as the square of the velocity. However friction and wear increases as velocity rises, so it is more effective to use a separate flywheel (of as large a diamneter as possible) and a significantly smaller diameter worm.
 

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*** Thanks for answers so far - I sort of knew much of it but wanted clarification - other perspectives help.

I suspected that overall friction may be the simple answer, but it still has the same effect on my head that the theory of flight does - I see and comprehend it well enough and can do the math to calculate it.... but the concept of how an aerofoil provides lift still raises an eyebrow when I look at an antonov or an A380 :) :).

Anyway...

Large worms and successfu flywheel effect are counter intuitive given the discussion and the data I have from the report... the larger worm means much more friction via surface contact per revolution so it reduces efficiency .....so the large diameter flywheel effect is a net zero or even less... clearly a "Bachmann marketing thought".. not an engineering one.

One of the conclusions of the report I mentioned was that the worm diameter should be as small as possible and the pitch of the worm thread as large (coarse) as possible to reduce friction and improve efficiency... which means no greater than say 10: 1 ~ 15:1 is really practical in stage 1 (worm and first gear) for reasonable efficiency.

The ONLY loco I have ever seen that came close was an old cold war era PIKO - the worm was fabricated via wire soldered straight to the motor shaft! It explains now why it actually ran very, very well... at the time I just considered it a primitive but clever answer to keeping cost low.

I wonder how practical turning the worm as part of the motor shaft design would be?

Interestingly most US diesels have a 12:1 ratio and are good at slow running and have excellent pulling power, but slow running high torque motors. 8 or ten driven axles is a good way of keeping power transfer acceptable of course... but its still food for thought

......... Hmmm

So a high speed box with a tiny coarse worm being the better compromise - perhaps we need to team them with either with a planetary box before the worm or added spur gear reduction between worm and axle.

Question: I wonder how the cost balance "bevel gear vs worm" looks when this is factored in? I suspect (OK, sort of know :) )that in the end the margin between them is going to be very thin indeed.

I'm sure a few eyes are glazed over about now

But.. It matters to me.... as a loco builder who also nows loco buiders who would also love to be able to use tiny motors with prodigious performance via efficient drives... and... while its not a money spinner.... I'd personally love to produce the answer as a DCCconcepts product as I have the suppliers that can do it... but how many other modellers really care.... Enough to make it worth doing? I wonder....

Richard
 

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Richard, re turning high efficiency worms on armature shafts, there are two examples that spring to mind.

Romford used to make a seven pole motor and gearbox assembly back in the fifties and sixties that had a coarse pitch worm turned into the armature shaft, it was also so efficient that the loco would often drive the gearbox after the power was turned off.

But even further back than that, in 1938 Meccano produced their first electric locos (a sort of N2 and recognisable A4) admittedly in 6volt so it could be powered from the accumulators that in those days powered many of the prewar radios. After the war a twelve volt version was made which had, and many thousands of then still have a vertical armature with a single start worm turned in the armature shaft, the motors used ballbearings as thrust bearings and were adjustable and very powerful when newly-magnetised.

Meccano then moved on in 1958 or so to their own ringfield motor, again designed in house and used in the Castle, Stanier Eight F, Light Pacific and D/E shunter all of which had the same style of motor. The Ring Field motor was huge and would only fit in the cab areas, I wonder if we would put up with that in this day and age.

A long time ago I had a long conversation with Brian Rogers of Ultrascale fame as he was developing a range of bevel geared motor gear box combinations and although I had one to try out, it was never as quiet as his worm and wheel gearboxes he produced for a while.

I, like a lot of others l know, have long abandoned the Portescap / Escap m/g as they have a inbuilt whine which no amount of tweaking seems to eradicate. Better to use one of Chris Gibbons excellent gearboxes with the silence of delrin gearing specailly developed for use in the motor drives of camers and videos.

Still, would be pleased to see what you come up with as an alternative.

Cheers
 

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Hi Wayne

How could I have forgotten my Dublo Duchess of Montrose which I was given in 1955 at age 3 as my first ever train set - it did indeed have a turned worm! Doop!

Re the portescap, I also gave up on them, removing the last two as the mosquito impersonation drove me to distraction. Related to this - an interesting true comment - We presented an RG4 to our supplier as an example of a generally suitable design type - the first words out of his mouth after looking it over were "they used the wrong mateial in the gears - I bet its noisy" :) :).

I too love Chris Gibbons / hi-level Gearboxes... I also quite like some of the NWSL stuff, but its getting a bit exxy with the exchange rate.

This whole subject gained momentum a year or so ago... because irrespective of gearbox, Mashima deliery has become to say the least patchy to pathetic and... more importantly, they seem to have changed their spec subtly and now have a tendency to overheat rather too easily when pushed hard compared to earlier models...

So... I've kept the project on the boil as Mashima is a tiny family business with no son to carry it on... and they are close to retirement.

The problem isn't the design any more - thats straightforward enough... its the quantity requirement at this point in time, and the associated commerical risk!

regards

Richard
 

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QUOTE (Richard Johnson @ 11 Mar 2009, 03:44) <{POST_SNAPBACK}>.. but how many other modellers really care ..
I care enough to be pleased that most of the better UK RTR now has a two stage reduction, by a fairly coarse worm, followed by a spur gear reduction stage. The reason why the older Bachmann 'fat worm' drives works as well as they do, is that the reduction ratio on the worm stage is fairly small. But the newer designs use smaller diameter worms that are still fairly coarse, which as you observe is better yet.

When building a chassis or installing a replacement drive in a chassis I would like to do it that way too, and always use a two stage box if it can be accomodated. But old habits die hard, and the usual worm/pinion combos economically available in the UK are higher reductions than is desireable, dating from the days of motor worm directly driving the pinion on the axle. Offer a fold up gear box kit with a fairly coarse worm, and adjustable reductions (and axle positions too ideally) via a spur gear set; all made in a low noise materials combination for the gear set, and I would be interested. This would be ideal for the typical small boilered 1/2/3 F 0-6-0 that is unavailable RTR, but so necessary for any UK steam era layout...
 

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Some food for thought. I have priced up replacing a Bachmann J72 chassis with a Comet. The total cost for chassis, wheels, motor, gearbox, hornblocks etc. is the far side of £75. Would one or two slightly more expensive gears make that big a percentage difference to the overall cost?

David
 

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Paul Hamilton aka &quot;Lancashire Fusilier&quot;
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That's where I was goin to go David too. I don't want to experience the pain of purchasing several wrong (or less appropriate) motor and gearbox combinations when someone can advise me of the better way to go. That's got to be worth 10 quid to me alone.

My last Mashima and Branchlines box purchase was purely based on the option presented by the particular kit manufacturer that supplied it with the chassis.

I was quite daunted by the prospect of the build and trust me when I say I read and read and read instructions over and over before starting anything.

Tell me or show me the "best" way and I will embrace it for sure, what ever the aspect of the hobby.
 

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I agree...with modern communications, we would save all that heart-ache of personal modelling developement, all that 'trial-and-error'?

All of which quite often leads to disillusionment and abandonment...
 
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