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George Ruthven
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Hi,
I'am wondering what the max wheelbase could be for single wheels under an O scale wagon. The curves are one metre diameter.
I want to build a few with 10 wheel sets and couplings I got from a friend. It'll have to carry a 2S Lipo batt, an ESC and receiver (on top I suppose) with sides and a lid - all from about 2 or 3mm plywood. And the axle bearings will be the grubscrews as so brilliantly proposed (could be by Si??) on this forum. 
Many thks,
George

Si.
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Hi George :wave:



My take on the maximum wheelbase would be ...

... whatever looks 'right' with your locos & other wagons.



The only thing I really worry about with longish 4-wheelers ...

... is possible 'overhang' at the ends, making the couplers potentially 'swing out' too much.

Keeping the wheelsets as close to the ends of the wagon as looks 'reasonable' is the answer to that one.

Depends a bit of course, on what couplers you're using as well.



Here's my 'cup-ended set-screw' method on an old 'Tri-ang' diescast HO underframe.

16.5mm gauge in this case & the screws are M3x3mm.














Sounds like FUN on the scratchbuild George !


I'm  s  l  o  w  l  e  y  doing a tender for my 1:35n2 Bachmann Porter 'upscale' ...

... I think for an R.C. setups, batteries, receiver & E.S.C. to go in.











R.C. can be 'affordable' even for bigger motors, my E.S.C only cost £2.54p inc. P&P ...

... & the 'FlySky' transmitter & receiver twin-pack, only cost me £16.00 inc. P&P.



Looks like it's going well there George, with your AC/DC motor stuff sorted as well. :thumb:



:)



Si.

George Ruthven
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Thks Si.
Yes going well except I'am waiting for my 3 Lipo's from China. Ordered in June and July and if you're up to date with South Africa then you'll know it's become normal. ALL gov systems falling apart. Fingers crossed it may arrive in Sept. In the meantime I have to keep the grandson enthusiastic by building things;). A friend cast some plastic Lima/Rivarossi couplings and after some experimentation even added a wire for strength. I find the couplings rather finicky (with the last run we had around the lounge (borrowed batteries) they often uncouple which is irritating) and may still sit down and consider something unconventional such as the tie bars on one's car. I see the guys using them on their RC buggys.

Only because in retirement there's the time to reconsider the workings of the world.

Last edited on Sat Sep 9th, 2017 02:59 pm by George Ruthven

W C Greene
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George, if you can handle them, link & pin couplers work all the time with no uncoupling (unless something breaks!). Then there's the old time method, cast "dummy" knuckle couplers. They hold together OK. I prefer the l&p's since the railroads I love and model tended to use them until the end.

Woodie

George Ruthven
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Thks Woodie but can I get that in English pse:shocked:?
Such a noobie.
I can Google them?
Or maybe you have pics?
L&p sounds like my kind of thing thks.
I worked 35yrs in metal manufacturing and promised myself after retirement I'll work in wood (was fortunate to do woodworking at school 1961 HA!).
So can I do any of this in wood maybe?

pipopak
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About the couplers if the rolling stock are roughly the same length you should have no problems.Jose

George Ruthven
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Ok, found lots of images on Google.
Am going to try some in wood.

Attachment: Link&Pin.jpg (Downloaded 43 times)

George Ruthven
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How about a single axle bogie or is that not acceptable?
That would enable me to have a long wheelbase?

I cannot seem to copy it into jpeg or directly here but it appears in images on Google. It's a BP wagon.

Last edited on Sat Sep 9th, 2017 06:17 pm by George Ruthven

Kitbash0n30
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I do not see it mentioned directly - the big issue with long wheelbase two-axle cars is flange binding, flange friction, and flange/railhead wear on curves.

Single-axle bogies can work, I believe LGB uses some on their gauge one rolling stock.

The question is what manner of mechanism to employ to keep the axle more or less square to the rails.
That, you are on your own to figure out.

As always, the best answer is to conduct practical tests of different wheelbase lengths on the track on which the cars will be running.

George Ruthven
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Thks yes I'am sort of developing (in my head) a length of plank (say 300mm) with a fixed axle at one end and an adjustable one at the other end. I'll start at the extremes and then bring the adjustable axle inwards (shortening the wheelbase) untill it runs smoothly.
I'll put a pic up next week sometime.
Maybe even a single axle bogie as well.

Si.
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Hi George :wave:



You said the curves are 1 Meter DIAMETER.

Did you actually mean 1 Meter RADIUS ?

L:

As Kitbash says, keeping a single axle bogies axle 'square' to the rails ...

... is in my view a big problem !


It seems to me that in doing so, a cars center of gravity, is gonna be WAY to one side ...

... & potentially 'toppleingly' unstable !!

:shocked:

Perhaps this is why I've NEVER seen such a prototype car.

A pair of universal, the world over, trucks, is obviously the 'standard' answer here.

:us:

When you said long wheelbase 4-wheeler ...

... I thought perhaps it might be eg. 6" long, NOT 12" !

:)

A good question might be ...

... what's the longest std. gauge 4-wheeler prototype you can find ?

If your scale is 1:48, I doubt any 1:1 prototype 4-wheeler is anywhere near 48 feet long !!

Even if it was, it's even more unlikely to have to negotiate super-tight curves.

???

I think any model needs to be engineered, 'more or less', like the prototype ...

... simply because the prototype has been made to operate properly.

:mex:

I pursued an idea a time back, for a 'whacky' slotcar steering & suspension system.

I was even convinced for a while that it might even work.

Guess what ?

It didn't !!



:moose:



Si.

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Si. wrote:
, I doubt any 1:1 prototype 4-wheeler is anywhere near 48 feet long !!

Even if it was, it's even more unlikely to have to negotiate super-tight curves.


Well, have a look here on page#3 Of course, this car will not easily negotiate curves of less than 75m(!) radius -which would scale out to 5feet in 1:48.
It has self-steering axles and the maximum train speed is >100km/h

Last edited on Sun Sep 10th, 2017 04:17 pm by Helmut

W C Greene
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I'm glad that I don't run 2 axle cars! Too much "engineering" and besides, I love "double truckers" anyway. As for 4 axles VS sharp curves (at least in narrow gauge) the little Gilpin Tramway and my fave, the SCPA&M, had 4 axle ore cars and others and many of the curves were 50' and 65' radius...in 1:48 scale, that's 12.5" for the 50 footer!
George, link & pin couplers were "outlawed" in common carrier railroads right after the turn of the 20th century but many industrial and private rr's used them to the end. Two that come to mind were the Monson RR in Maine, a 2 footer with l&p's until it closed in 1941 and out in California, the West Side Lumber Co. (and some others) used them as late as 1960-I know because I was there in 1961 and many of the cars had them and the locos had slotted knuckle couplers so they could hook up with the older cars. Very interesting. But now, this is perhaps a "US thing", I'm not familiar with what was used across the pond.

Woodie

Salada
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My scratch built 8' and 9' wheelbase, 4 wheeled, two rigid axle wagons will "fairly" easily traverse 22.5" radius complex trackwork that is actually less than 20" right at the apex of the curve through the common crossing (frog). There is some REAL flange squeal and anything above about a scale 8-10mph would be impossible. Mr Woodie is quite correct, the couplings are the real problem. I use scale 3 link hook & chain couplings but I have had to slightly increase the link lengths to get around tight curves. I also use my own system of fully independent axle suspension, none of this modeller's "compensation" funny stuff - which is nothing like how the real thing works on 2 axle freight wagons - though I doubt if this makes any difference to the minimum radius capability.

My short wheelbase, 12' spread over 3 rigid axles, six wheeled heavy freight brake (caboose) vans need a minimum 28"-30" radius, even with their Salada Wagon Works patent central axle design.

I have some long rigid wheelbase (18') 2 axle, 4 wheeled bolster/rail wagons that need a minimum 30"+ radius in trials on another layout.

Keep your axles square and parallel and dead level. Don't increase track gauge on tight curves, that leads to even more problems later on. I work in Imperial O Gauge, 43.5:1 standard gauge, all wagons totally scratch built other than wheels and axle box castings.

8' wheelbase, 8/10 ton coal wagon on 20" radius pointwork :



Yeah, I know its upside down, beyond my computer skills to manipulate an FR Gallery photo.

Hope this helps you.       Regards,   Michael 

Si.
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Hi George :wave:



I dunno about Helmuts 'euro-wagon' example ? L:

Might have been designed by a QANGO in Brussels ! ;)


But ...


Saladas modeling from his time on the International Space Station, is peerless. :shocked:

His anti-gravity braking system & Zero-G coal loading techniques, are both pioneering research. :brill:



:moose:



Si.

Helmut
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Well,
those eschewing the Continentals may easily mix up Swiss entrepreneurship with Brussel sprouts. Transwaggon is a Swiss firm for 52 years!

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Si. wrote:

L:

As Kitbash says, keeping a single axle bogies axle 'square' to the rails ...

... is in my view a big problem !


It seems to me that in doing so, a cars center of gravity, is gonna be WAY to one side ...

... & potentially 'toppleingly' unstable !!

:shocked:

Perhaps this is why I've NEVER seen such a prototype car.

A pair of universal, the world over, trucks, is obviously the 'standard' answer here. "
                                        xxxxxxxx
 
Axles must ALWAYS be square to the railhead across the rails otherwise disaster awaits at any facing point trackwork, guard rail, etc. A proper functioning suspension system, preferably fully independent like the real thing, will cope with any variation in railhead height across the tracks but still keep all flange faces square to the railhead. But there is no cure for rigid 2 axle X/S wheelbase where the squareness of the flange faces grinds the flanges against the inner railhead face.
 
My test for all scratchbuilt 2 axle, 4 wheel model stock is that ONE wheel must stand on an Imperial 5 penny coin (.067") without raising the wheel on the opposite end of the same axle and whilst the other 3 wheels sit flat on a flat test bed. Any fail has to go back to The Works. In practice in both prototype and model scales the CG should never lie outside the track radius CL, excluding perhaps some 'mini-pizzas' so toppling over is not a problem. 

Si, wagons like Helmuts are in use in various countries, we even had/have some here but I haven't seen one for ages. I had a photo of a similar SG Italian wagon but the FR Gallery has mysteriously eaten it (my pics went haywire during/after THE Big Crash at FR - now all in completely random order with many "disappearances")(NOT your fault !).

Photo of an FDC (Italy) NG wagon that I guess cannot be less than 18'-19' long over the couplers on about a ? 10'-11' wheelbase. Some weird Euro gauge about 850/860 cms (whatever they were post EU) with fairly tight curves (the track, not the Italian lady passengers) :




IMAGE DELETED




Oops, photo has a credit but I'm sure I took one identical (not noticed until after posting - maybe that's why it's from the FAL system and not the FDC)

Regards,   Michael
  

Last edited on Sun Sep 10th, 2017 11:44 pm by

Salada
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Si. wrote:
His anti-gravity braking system & Zero-G coal loading techniques, are both pioneering research. :brill:

You've been taking a sneak look at the Salada Wagon Works' experimental Dept again.

Be afraid, VERY afraid !!!

Regards,   Michael

Si.
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" NOT your fault ! "



Hi Michael :wave:



Correct-a-mundo !

I don't break stuff ... I fix stuff.

I guess I will continue to hear about it, until I am in my grave though !! :y:



The 'Freerails Gallery' BTW, cannot possibly turn photos upside-down in a million years.

If your photos have become 'jumbled', I am amazed, cos no one else has ever reported this.

Indexing of some Threads was affected ... ( BEFORE my time of course, I just mopped up after )

... but the Members Gallery, other than yours it seems, was untouched. L:



I guess I could take early retirement. :old dude:



:P



Si.



After all it's not that awful.
You know what the fellow said,

in Italy, for thirty years under the Borgias,
they had warfare, terror, murder & bloodshed,
but they produced Michelangelo, Leonardo da Vinci & the Renaissance.

In Switzerland, they had brotherly love,
they had five hundred years of democracy & peace,
and what did that produce ?

The cuckoo clock.

So long Holly.

George Ruthven
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Thk you all - great info.

Maybe I only need 1" more - I'll know as soon as the Lipo's arrive

In the meantime I'll experiment:Crazy:

Helmut
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@Si
tz.tz. The Swiss did not invent the cuckoo-clock,
it is a genuine black forest product.
The Swiss may not have been so blood-thirsty, but they gave the world e.g. precision clocks and gears. Ever heard of a reliable Italian watch?

Si.
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Ever heard of Orson Welles ?


:moose:


Si.

Helmut
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Of course I have.

George Ruthven
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I was so inspired by Woodie's advice I set out early and found some standard flat plates, washers, a single chain link and a split pin to put together a link & pin system.

Some drilling and voila I think this is the answer to my grandson's woes (close to tears)  every time a wagon(s) uncouples.

The length from wagon chassis to split pin seems a bit much - will check with the existing plastic ones - don't want the distances between wagons to look unnatural or have him grow up with faked realities:)

Next is the wheelbase experiment.

Attachment: Link&Pin1.jpg (Downloaded 21 times)

George Ruthven
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and another view

Attachment: Link&Pin2.jpg (Downloaded 22 times)

Si.
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I think THAT'S worth 5 Einsteins ! ! ! ! !



:brill: :brill: :brill: :brill: :brill:



Si. :thumb:

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Hi George,

Have a look at page 19 and 20 at http://www.hse.gov.uk/pubns/mines06.pdf, specifically the calculation for minimum radius of 4-wheel wagons. 


The link is to specifications for underground mining equipment in the UK. With a known curve radius you can work backward to get a maximum wheelbase to avoid flange-lifting. Note that the wagon weight does not appear to be part of the equation. There is probably some fudge factor in the equation but I wouldn't like to guess or calculate how much from first principles,

George Ruthven
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Thks Si, thks John - super document.
George

W C Greene
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That's the way George! It DOES look like it should. I am sure that somewhere there's a prototype for the couplers. I sort of reminds me of the "radial" couplers used on streetcars and other industrial types.
Maybe a bit of rusty paint (or not) and you're in business.

Woodie

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Thanks for the mines publication, John.
George, if there wasn't a real coupler like that there might should have been; either way, it ultimately _is_ prototypical because it _is_ the prototype!

George Ruthven
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To finesse it I'am looking for BLANK washersL:.

What a wonderful hobby........

pipopak
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A potty car... with lotsa flushing water!Jose.

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Jose
You are spoiling the miners - Yes there have been underground potty cars aka "dunny's on rails" on here previously. What's a flush?? And does it beat four aces and Colt?? :) 

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I've built my wheelbase testing unit with the following possible wheelbases
(starting at 105mm)
which is slightly longer than the wagons I have: 123; 138 and 150mm maximum.

See the holes holding the bearings (grub screws) for adjustment.

I also used John's equation of B=2RS/L with B=wheelbase, R=radius, S=difference between track and wheel width (1.7mm on the wheels), and L which is a separate calculation as a relation between wheel radius and flange depth and mine equated to 16.27.

It gave a wheelbase of 146mm.

BUT from the pics it already seems not feasible. 

Nevertheless I will run all the wheelbases and report back as soon as the postman arrives:).

Attachment: Tester2.jpg (Downloaded 24 times)

Last edited on Sun Sep 17th, 2017 12:34 pm by George Ruthven

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and

Attachment: Tester1.jpg (Downloaded 24 times)

George Ruthven
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The first pic shows the wheels already pointing North:)

It does go well given a vigorous push!

Attachment: Tester3.jpg (Downloaded 25 times)

Last edited on Sun Sep 17th, 2017 12:43 pm by George Ruthven

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George,

Always a good idea to build a test rig first.

There is a system used by some modellers of vintage passenger stock that have 3 rigid axles (1 near each end and 1 'amidships') that I have seen used successfully.
Each axle/axle box unit looks rigid but is actually pivoted at mid axle to allow some swivel around that central point. These axle 'units' (2 axle boxes + 1 axle) are then laterally connected together by a light longitudinal spring wire under the floor that maintains some light control over the axle units but allows sufficient pivot to negotiate curves. I've not used this system myself. I don't know how they manage the solebar suspension springs, brake shoes & rodding etc. Should also work on 2 axle vehicles ??

Regards,    Michael

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Hi George,
Some other points to watch for -
  • Coupler swing - If the head of the coupler is outside the outer rail then you are very likely to end up with derailment problems due to the amount of sideways loading transferred back to the chassis from the coupler.
  • distance of axle from end of vehicle - the closer you can get your axle to the end of the vehicle then the more you can reduce the amount of coupler swing - check out the difference at each end in the photos you have posted. 
  • The further you axles are out toward the end of the wagon, then the you need a bigger clearance for the wagon on the inside of the curve. You can quickly test this by fastening a pencil to the middle of the wagon on the inside of the curve, and move the wheels to a different position and watch the path traced by the pencil along the curve. (Remember to move the pencil so that it is central to the changed wheelbase for most obvious "worst case"results)
  • Salada has mentioned the linkages between swivelling axle boxes. Look for "Cleminson" suspension and "radial truck" for more information. 
  • Also there should be some information on the steerable bogies used under some EMD high-horsepower locomotive like  https://www.google.com/patents/US6871598
  • Also consider using check rails that bite on the back of the inside flanges. This should help to avoid flange-climbing on the outer rail. For a quick and dirty test, strip a length of rail, bend to follow the inner rail and butt the foot of this rail up against the moulded rail fasteners - supuerglue this check rail in position. It won't be accurately gauged but it should be "close-enough". In that the flange should pass through in the gap OK  and the back of the wheel should rub against the inner edge of the check rail enough to prevent the leading flange on the outer rail from climbing.  
    Just some other stuff to play with while you are in "experiment mode". It's an interesting test rig and I'll be honest on that I haven't seen done before. 

Salada
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John & George :

Well done John. "Cleminson" is the name of the method but I'd forgotten that.
Yup, 'working' check rails DO work. My fledgling colliery model uses them on the bits built so far; also 'working' Xing guard rails.

Regards,    Michael

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John & George :

Increasing the weight of wagons of doesn't prevent flange climbing, neither in 'O' Gauge (tried it) nor 20" gauge cable hauled mine incline - see photo below:





Mine trams always try to climb this outer switch rail, not helped by the cable roller position. I loaded the little swivelling/end tipper seen in the distance to about 12 cwt but it made no difference. Looks like breakfast was burning !.

Photo by Salada.

Regards,     Michael

Last edited on Tue Sep 19th, 2017 11:49 pm by Salada

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Thanks again for the suggestions - we went off to see some flowers and game (lion and cheetah, 2 rhino's and some large buck) - and I must get my grey matter together again.

AND yay the batteries arrived this morning - will lay some track next week and start testing.

George

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Found this on FB O guage group. Interesting that the formula's result was 146mm.
Kevin Gill Hi George the wheelbase is 147mm. Hope this is of some help.


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