Trainworx N-scale Mini-89 (M89) Coupler Testing

[Mark5]

I'd agree with @robert3985, that an 11% size reduction simply is not worth the bother, JMHO. It's very marginal appearance improvement, yet nowhere near enough if appearance is an important factor.   Then do you convert everything (time + expense) only to have to do it all again for the next 11% that comes along (if it ever does)?

Ed

Well, I disagree (if it was actually available to buy) - 11% coupled with no slink could be worth the bother (at least to me). Moot question though since it is not really available.

I've been watching for decades hoping to see a readily available better coupler solution, but I'm still waiting ...

N scale doesn't even have any off the shelf extended draft year options as yet, and we are 1/5th into the 21st century. 

Mark

[ednadolski]

... 11% coupled with no slink ...

Oh yes, no slink by itself is more than worth the price of admission, any size improvement would be gravy.

With the LEZs tho I have both (and near-scale air hoses to boot)


Ed

[ncbqguy]

Yes, the Arnold Rapido / Hornby coupler used on the U25C and SW1 were based on my design.  The execution was done without pre-production testing to fine tune the spring and insure compatibility with MT by their engineering staff.
Mark Runyan and I have been trying to get somebody to implement the design.   If I were younger I would start a company and tool and sell it OEM and retail the coupler myself.   Instead I would give the design to whoever will implement it royalty free for the consideration of enough raw parts to re-equip a portion of my equipment.  (I need to divest myself of way too much collection).  The initial design was developed from my outline specifications in my family room during “Wednesday Night Railroaders” sessions.  We almost had BMLA implement it but his Chinese factory “saw no need for another coupler” and refused to tool it.
A wrinkle is that Mark does his 3D CAD magic for several clients and he has separately offered the design to them.  As he has done all the 3D CAD work he has a claim to the work as well....I just want to see a decent looking coupler in N.  One of his clients is supposedly working on a version but it hasn’t involved me.
One can’t just shrink a coupler and add detail.  The average N Scale layout has track that will uncouple small couplers vertically.   Hence the key concept that I laid out is the extended post on the knuckle.   It adds negligible mass to the coupler yet maintains the “vertical gather” of oversized couplers.  A fixed pivot to eliminate “slinky”was another key goal.  I also think a metal spring is necessary as tiny plastic whiskers don’t have the precision and durability of metal.  As recently as a couple of months ago I had Mark draw up what I believe to be a workable manufacturable simple formed wire spring concept.  I have mocked up oversized samples and I think it is “The Final Solution”.
Charlie Vlk
N Scaler since 1964 and
Railroad Model Resources

[wazzou]

I was just thinking that small diameter Phosphor Bronze wire replacing the molded plastic whiskers would be the most elegant soloution.

[peteski]

I was just thinking that small diameter Phosphor Bronze wire replacing the molded plastic whiskers would be the most elegant soloution.

Or spring-temper stainless steel wire.  Most of the contemporary kinematic-type Rapido coupler arms in European models use 0.1mm (0.004") stainless steel wire for centering the arm.  I suspect that something like 0.002" SS wire would be a good whisker material for centering knuckle coupler shanks.

Charlie: you are making some interesting points, which is not surprising going by your professional background.  Also interesting about the factory refusing to produce those couplers. This again shows that the American companies do no have full control of their Chinese contractors.  Which is too bad.

[ncbqguy]

Peteski-
To be fair, one of the factory owner’s objections turned out to be correct.   Originally the design called for a U-spring formed out of sheet...somewhat like the centering spring in a Kadee 5&10 but without the floor.   It proved to be too small and too delicate to manufacture.  Everybody has to respect each other’s craft.
When we built our retirement home I had to go out of my way to convince the trades that, while a registered architect, I did corporate facility management and wanted them to built it as if they were doing their own home.  I got a really nice home as a result.
We need a small detailed coupler because we worry about things like working scale ditch lights and then stick a oversized coupler on the front of the unit that screams N Scale!
Charlie Vlk

[peteski]

Peteski-
To be fair, one of the factory owner’s objections turned out to be correct.   Originally the design called for a U-spring formed out of sheet...somewhat like the centering spring in a Kadee 5&10 but without the floor.   It proved to be too small and too delicate to manufacture.  Everybody has to respect each other’s craft.

My statement was not just based on the example you brought up. I have heard that the Chinese manufacturers for example refuse to produce spare parts or undercoated bodies while they are doing a run of models.

[Lemosteam]

More on small couplers:

https://www.therailwire.net/forum/index.php?topic=51313.0