Kadee Scale Coupler Operational Reliablity


Tim O'Connor
 

I think production issues killed it -- could not be made as
was desired. But I was never happy with JP Barger's idea of
making it compatible with the Kadee #5 shank. A true scale
coupler and scale draft gear, now that would have been good
(for some of us).

Tim O'Connor

At 2/23/2010 04:13 PM Tuesday, you wrote:
Gentlemen,Whatever happened to the reboxx coupler?Armand Premo


Armand Premo
 

Gentlemen,Whatever happened to the reboxx coupler?Armand Premo

----- Original Message -----
From: soolinehistory
To: STMFC@yahoogroups.com
Sent: Tuesday, February 23, 2010 3:48 PM
Subject: [STMFC] Re: Kadee Scale Coupler Operational Reliablity





--- In STMFC@yahoogroups.com, Denny Anspach <danspach@...> wrote:
>
> Dennis Storzek writes-
>
> > Note that the locomotive was originally delivered with short swing
> > knuckles, similar to those used on steam locomotive pilots:
>
>
> Dennis, this is a new one to me. Just what made up a "short swing
> knuckle"?
>
> Denny
>
> Denny S. Anspach MD
> Sacramento

Aw, com'mon Doc. You're not going to make me spend hours looking for a photo on the web, now, are you. If there is a more descriptive name, I don't know it, but what I mean is the knuckle with the short tang on the back, only long enough to suround a pin, that pins into a pocket bolted to the face of a pilot beam; basically the standard steam loco front coupler before drop couplers became all the rage. The couplers that were used on Shays were similar, but had two tangs, and could be adjusted for height by pinning them in different slots ina pocket with several slots.

Wait, this is what I meant, from the Sergent Engineering web site:

http://www.sergentengineering.com/images/Pocket1_2.jpg

The coupler does not go through the pilot beam, it's short, and has very limited swing.

Dennis






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Stokes John
 

Precision Scale has a number of such couplers in its line, not working automatics, but are attached as described, and several coupler pockets for locos that use this type coupler. It can be done with Kadees or knock-offs by cutting the shanks short and filing them to fit, and attaching with a rod through the shank and pocket.

John Stokes
Bellevue, WA

To: STMFC@yahoogroups.com
From: destorzek@mchsi.com
Date: Tue, 23 Feb 2010 20:48:55 +0000
Subject: [STMFC] Re: Kadee Scale Coupler Operational Reliablity
































--- In STMFC@yahoogroups.com, Denny Anspach <danspach@...> wrote:

Dennis Storzek writes-
Note that the locomotive was originally delivered with short swing
knuckles, similar to those used on steam locomotive pilots:
Dennis, this is a new one to me. Just what made up a "short swing
knuckle"?
Denny
Denny S. Anspach MD
Sacramento


Aw, com'mon Doc. You're not going to make me spend hours looking for a photo on the web, now, are you. If there is a more descriptive name, I don't know it, but what I mean is the knuckle with the short tang on the back, only long enough to suround a pin, that pins into a pocket bolted to the face of a pilot beam; basically the standard steam loco front coupler before drop couplers became all the rage. The couplers that were used on Shays were similar, but had two tangs, and could be adjusted for height by pinning them in different slots ina pocket with several slots.



Wait, this is what I meant, from the Sergent Engineering web site:



http://www.sergentengineering.com/images/Pocket1_2.jpg



The coupler does not go through the pilot beam, it's short, and has very limited swing.



Dennis


Dennis Storzek
 

--- In STMFC@yahoogroups.com, Denny Anspach <danspach@...> wrote:

Dennis Storzek writes-

Note that the locomotive was originally delivered with short swing
knuckles, similar to those used on steam locomotive pilots:

Dennis, this is a new one to me. Just what made up a "short swing
knuckle"?

Denny

Denny S. Anspach MD
Sacramento
Aw, com'mon Doc. You're not going to make me spend hours looking for a photo on the web, now, are you. If there is a more descriptive name, I don't know it, but what I mean is the knuckle with the short tang on the back, only long enough to suround a pin, that pins into a pocket bolted to the face of a pilot beam; basically the standard steam loco front coupler before drop couplers became all the rage. The couplers that were used on Shays were similar, but had two tangs, and could be adjusted for height by pinning them in different slots ina pocket with several slots.

Wait, this is what I meant, from the Sergent Engineering web site:

http://www.sergentengineering.com/images/Pocket1_2.jpg

The coupler does not go through the pilot beam, it's short, and has very limited swing.

Dennis


Dennis Storzek
 

--- In STMFC@yahoogroups.com, "Aley, Jeff A" <Jeff.A.Aley@...> wrote:

Dennis,

I believe that the kingpin-to-kingpin distance is also critical, and this is where the curvature really comes into play. The two kingpins are points on an arc of a circle (assuming constant radius), and the more degrees of arc they encompass, the worse the problem will become (imagine a car and track such that the kingpins extend over 180 degrees of arc!)
Thus, I believe it's a combination of the kingpin - to -kingpin distance, as well as the kingpin to striker distance, as well as the curve radius that causes our problems.

Regards,

-Jeff
I can't say I disagree, although I usually point out the end overhang difference, as once pointed out, it becomes readily apparent where the problem lies. However, cars or locos with a large distance between the coupler and striker also tend to have long truck centers, and the additional angular displacement just exacerbates the problem.

Before anyone thinks I'm picking on modern diesels, the same problem exists when mixing long passenger cars with freight cars, and when trying to use the pilot coupler of a steam loco for switching. Model steam locos are a partial curse; the tender often has coupler geometry most like that of a freight car, but since the locomotive tends to pivot about the center of it's rigid driver wheelbase (few model locomotives have fully functional pilot trucks that actually guide the loco into curves) the pilot couler tends to be a long way off the track centerline when in a curve.

Dennis


Denny Anspach <danspach@...>
 

Dennis Storzek writes-

Note that the locomotive was originally delivered with short swing
knuckles, similar to those used on steam locomotive pilots:

Dennis, this is a new one to me. Just what made up a "short swing
knuckle"?

Denny

Denny S. Anspach MD
Sacramento


Aley, Jeff A
 

Dennis,

I believe that the kingpin-to-kingpin distance is also critical, and this is where the curvature really comes into play. The two kingpins are points on an arc of a circle (assuming constant radius), and the more degrees of arc they encompass, the worse the problem will become (imagine a car and track such that the kingpins extend over 180 degrees of arc!)
Thus, I believe it's a combination of the kingpin - to -kingpin distance, as well as the kingpin to striker distance, as well as the curve radius that causes our problems.

Regards,

-Jeff


From: STMFC@yahoogroups.com [mailto:STMFC@yahoogroups.com] On Behalf Of soolinehistory
Sent: Monday, February 22, 2010 12:58 PM
To: STMFC@yahoogroups.com
Subject: [STMFC] Re: Kadee Scale Coupler Operational Reliablity




--- In STMFC@yahoogroups.com<mailto:STMFC%40yahoogroups.com>, "railwayman" <stevelucas3@...> wrote:

I think that it's time that we had a look at prototype couplers, in keeping with the STMFC list's mandate.

My 1995 AAR Field Manual gives coupler dimensions for Type E couplers. Rule 16, paragraph 8 gives a distance of 21" (.241" in HO) from back of the head to the end of the shank on a BE60AHT coupler, as well as several other Type E's. My belief is that this is a standard coupler length found on STMFC's...
Think about how much swing a prototype coupler can achieve on an 11 1/4" radius for a moment. It becomes clear that a standard Type E coupler is very tolerant of sharp track radii. Such as here, on the Bronx Terminal--

http://members.trainweb.com/bedt/indloco/crrnjbxtphoto2.jpg

http://members.trainweb.com/bedt/indloco/crrnj10009.jpg

Notice the boxcar on a less than 100' radius curve next to the curved freight shed in both photos.
Steve,

Your study of the key slot dimensions of the AAR Type E coupler is interesting. In all my work designing couplers, I have never bothered to calculate the effective pivot location of a prototype coupler... Thanks.

However, your use of the Bronx Terminal as an example is misleading. The main thing that drives the need for wide swinging couplers on our models isn't the length of the coupler shank; that's the effect, not the cause. The main thing that forces us to need wider than prototype swing is our desire to run equipment with different king pin (truck pivot) to striker (or coupler pulling face, take your choice) dimensions, because the longer that dimension, the further from the track centerline the coupler is thrown on curves.

In the case of the Bronx terminal, all the cars had the almost universal standard of either 5'-0" or 5'-6" to striker distance. The only exception was the locomotive, which was somewhat longer, although I can't find a dimension at the moment. Even so, this is a very short locomotive; note there are no steps between the outer axles and the end sill. Even as short as this locomotive is, the CNJ must have found lack of coupler swing troublesome. Note that the locomotive was originally delivered with short swing knuckles, similar to those used on steam locomotive pilots:

http://sbiii.com/jfcageir/ageir5.html

Which the CNJ changed to a short knuckle pinned to a radial drawbar:

http://www.toytrains1.com/images/trains/bo-2002-14.jpg

Your first photo above also shows this arrangement to good advantage.

Unfortunately, these early boxcabs are atypical of later diesels, which have kingpin to striker dimensions in excess of 12'. This throws the coupler so far off track centerline on sharp curves that the coupler on the coupled car actually swings OUTWARD, toward the outside of the curve, in order to remain coupled to the locomotive. If the coupler can't offset a sufficient amount, the car will be dragged off the rails. This is a situation that just doesn't exist on the prototype, for all practical purposes.

The solution to his problem, dating to toy train days, was to fit wide swing couplers to all the equipment, similar to what was done to the prototype CNJ 1000. The solution today, for prototype modelers, should be to simply not try to run trains on curves that the prototype equipment can't deal with, but that only applies to prototype modelers. The bulk of the hobby dollars are still spent by the guys who want to run their SD50MAC's or whatever they are on a 4' x 8' sheet of plywood, and that's the market the manufacturers need to keep foremost in mind.

Dennis


Dennis Storzek
 

--- In STMFC@yahoogroups.com, "railwayman" <stevelucas3@...> wrote:

I think that it's time that we had a look at prototype couplers, in keeping with the STMFC list's mandate.

My 1995 AAR Field Manual gives coupler dimensions for Type E couplers. Rule 16, paragraph 8 gives a distance of 21" (.241" in HO) from back of the head to the end of the shank on a BE60AHT coupler, as well as several other Type E's. My belief is that this is a standard coupler length found on STMFC's...
Think about how much swing a prototype coupler can achieve on an 11 1/4" radius for a moment. It becomes clear that a standard Type E coupler is very tolerant of sharp track radii. Such as here, on the Bronx Terminal--

http://members.trainweb.com/bedt/indloco/crrnjbxtphoto2.jpg

http://members.trainweb.com/bedt/indloco/crrnj10009.jpg

Notice the boxcar on a less than 100' radius curve next to the curved freight shed in both photos.

Steve,

Your study of the key slot dimensions of the AAR Type E coupler is interesting. In all my work designing couplers, I have never bothered to calculate the effective pivot location of a prototype coupler... Thanks.

However, your use of the Bronx Terminal as an example is misleading. The main thing that drives the need for wide swinging couplers on our models isn't the length of the coupler shank; that's the effect, not the cause. The main thing that forces us to need wider than prototype swing is our desire to run equipment with different king pin (truck pivot) to striker (or coupler pulling face, take your choice) dimensions, because the longer that dimension, the further from the track centerline the coupler is thrown on curves.

In the case of the Bronx terminal, all the cars had the almost universal standard of either 5'-0" or 5'-6" to striker distance. The only exception was the locomotive, which was somewhat longer, although I can't find a dimension at the moment. Even so, this is a very short locomotive; note there are no steps between the outer axles and the end sill. Even as short as this locomotive is, the CNJ must have found lack of coupler swing troublesome. Note that the locomotive was originally delivered with short swing knuckles, similar to those used on steam locomotive pilots:

http://sbiii.com/jfcageir/ageir5.html

Which the CNJ changed to a short knuckle pinned to a radial drawbar:

http://www.toytrains1.com/images/trains/bo-2002-14.jpg

Your first photo above also shows this arrangement to good advantage.

Unfortunately, these early boxcabs are atypical of later diesels, which have kingpin to striker dimensions in excess of 12'. This throws the coupler so far off track centerline on sharp curves that the coupler on the coupled car actually swings OUTWARD, toward the outside of the curve, in order to remain coupled to the locomotive. If the coupler can't offset a sufficient amount, the car will be dragged off the rails. This is a situation that just doesn't exist on the prototype, for all practical purposes.

The solution to his problem, dating to toy train days, was to fit wide swing couplers to all the equipment, similar to what was done to the prototype CNJ 1000. The solution today, for prototype modelers, should be to simply not try to run trains on curves that the prototype equipment can't deal with, but that only applies to prototype modelers. The bulk of the hobby dollars are still spent by the guys who want to run their SD50MAC's or whatever they are on a 4' x 8' sheet of plywood, and that's the market the manufacturers need to keep foremost in mind.

Dennis


railwayman <stevelucas3@...>
 

I think that it's time that we had a look at prototype couplers, in keeping with the STMFC list's mandate.

My 1995 AAR Field Manual gives coupler dimensions for Type E couplers. Rule 16, paragraph 8 gives a distance of 21" (.241" in HO) from back of the head to the end of the shank on a BE60AHT coupler, as well as several other Type E's. My belief is that this is a standard coupler length found on STMFC's. Here's a sketch of a Type E coupler--

http://www.greatlakesrailcar.com/Couplers/AAR%20typeE.jpg

This coupler is condemned if the back of the draft keyslot is less than 3 3/4" from the end of the shank. This gives a rear key slot distance of 17 1/4" (.198" in HO) from the rear of the coupler head. An AAR standard draft key is 6" long on its flat side. Assuming a keyslot of the same length on a Type E coupler, we deduce a length of 11 1/4" (.129" in HO) from front of keyslot to the back of the coupler head.

So in draft, the radius that determines coupler swing on a car with a standard length Type E coupler is 17 1/4, and in buff, 11 1/4".

Think about how much swing a prototype coupler can achieve on an 11 1/4" radius for a moment. It becomes clear that a standard Type E coupler is very tolerant of sharp track radii. Such as here, on the Bronx Terminal--

http://members.trainweb.com/bedt/indloco/crrnjbxtphoto2.jpg

http://members.trainweb.com/bedt/indloco/crrnj10009.jpg

Notice the boxcar on a less than 100' radius curve next to the curved freight shed in both photos.

Tim Warris of FastTracks (http://www.handlaidtrack.com/index-2.php) is building an excellent model of the Bronx Terminal in HO, using cars fitted with what appear to be standard NMRA draft gear on curves of about 12" radius--

http://www.bronx-terminal.com/

And here is where I think that we get tripped up in modelling scale draft gear boxes--NMRA RP-22 (original Ken Mortimer drawing date of August, 1958) gives a distance of .265" in HO from the centre of a .060" diameter coupler pivot to the face of the cover plate (ie. where the head of the coupler is shoved against in buff).

http://www.nmra.org/standards/sandrp/pdf/rp-22.pdf

A Kadee standard coupler pocket, #232, used on many of their couplers, including likely the most popular HO couplers used by STMFC modellers, #'s 5 and 58, (yes, I know that many on this board are using Sergent couplers now) has a measurement of .254" (maybe my measurements are a bit off--I'm thinking that this is a nominal 1/4" actual distance) from end of cover plate to centre of coupler pivot stem (which the coupler pivots on).

http://www.kadee.com/htmbord/page232.htm

With a Kadee #5 or #58 coupler's depth from back of coupler head to centre of pivot being about .270", we have about twice the distance between pivot point and back of coupler head on the Kadee coupler compared with the Type E's HO scale measurement of .129" in buff between pivot (the front of the draft key) and the back of the coupler head.

So the Kadee coupler box HAS to be wider than scale to accommodate "sharp model radii"--but remember the real Bronx Terminal? They were able to take 40' and longer cars with standard AAR draft gear around curves of less than 100' radius--less than 14" radius HO curves. And their train crews were able to couple and uncouple cars on these curves.

The culprit is the distance between coupler head and pivot point (or if you want to be even more accurate, the distance between pulling face of coupler and pivot point) on the model couplers that we use now. Shorten it, and we can have scale width coupler boxes. But then of course, we "need" those coupler centreing spring that mostly weren't used on STMFC's, barring Cardwell draft gear...

But it'll take some subtle or not-so-subtle pressure on the major manufacturers to have working scale width draft gear in something other than a niche product. It CAN perform well on those "sharp model railroad curves".

Steve Lucas.

--- In STMFC@yahoogroups.com, Jim Betz <jimbetz@...> wrote:

Denny, et al,

While I agree that the standard length of the shanks on
the Kadee product line (and all other mfgrs as well - with the
possible exception of the Sergents) is longer than it should be -
it does mean that we can operate our model trains on track with
significantly more curvature than the prototype. The same can
be said of the width of the coupler box - and that measurement
is directly related to the same thing.

I have never seen a layout that has truly prototypical
curvature standards. And even those that have truly generous
standards (such as "nothing smaller than 36" on the mainline")
still have several areas on the layout that have smaller
curves and lower numbered turnouts. If I remember correctly
a #10 turnout -approaches- the typical smallest radius of the
prototype (and I'm not talking about mainline). Yes, of course,
these are generalizations/standard practices and you can go
out and find examples where the real RRs had more curvature
than these statements. But they are pretty close to what
the real RRs use as their standards (which they may or may
not break depending upon the situation).
On our layouts we 'fudge' even our own standards - not once
in a while but often/always. The phrase "I can make it fit if
I use a #4 turnout here for this industry track" is one I hear
a lot. The other thing you hear are statements such as "we
have 30-inch radius every where on our mainline - except for
the areas at _____ and _____" ... and those statements are made
proudly/as a brag about how generous that particular layout is.
And there is a real reason why the time-saver is based upon
all #4 turnouts.
If I remember correctly I think that an HO layout would
have to adopt s curvature standard of something approaching
that used on O-scale in order to be in the same ball park as
the real RRs.
I can't remember ever seeing a commercially available
turnout number larger than a #10. Even Fast Tracks only
goes up to a #12 (and I'll predict that they don't sell very
many of them!) - in HO and N ... and they only go up to a #6
in O-scale.

If you can get Kadee (or any other coupler mfgr) to answer
you I'm certain that you will find that the size of the coupler
box and the length of the shank has been chosen in order to
provide for operation of normal length equipment on tight
radius curves (where tight is defined as 22" or larger - at
least). The other thing that you will be told is that they
are using the sizes/measurements they are using due to the
NMRA standards/RPs.

Until we start to have layouts that do not compromise on
the curvature and turnout numbers in use I'm afraid we are
going to have to compromise on the coupler boxes and shanks.
I don't see any way around it.
I'll even go further and state that due to the sheer
number of layouts and existing model trains that are
already out there already you are going to be hard pressed
to figure out how to influence/change this reality. We may
be 'committed' to this state "for ever". *Sigh*
On the other side - I'm not sure any of us would ever
attempt to build a layout based upon true prototype
curvature standards ... we just don't have the space.

One last thing - all of the above relates directly to
the operational characteristics of our 'typical' trains and
is equally applicable to all scales and eras. If your layout
is early enough in the STMFC era that you have only 40'
or shorter freight cars then you might be able to use
smaller boxes and shorter shafts. Even a train of all
50' cars, going around a 40" radius curve - will look 'funny'
when compared to the real RRs. By 'funny' I mean that the
cars will be hanging out over the rail in the middle of the
car further than you will see them do on a real RR.
- Jim

P.S. It certainly -seems- to be true that having a coupler
box available that has a 'built-in shim' across the
opening to prevent coupler droop would be a good idea.
But I highly doubt we'll ever see it from Kadee - if
for no other reason than that it would prevent that
box from being used for a #5 with the existing copper
centering spring.
A good argument can be made for the idea that a
coupler "needs" to be able to 'droop' during certain
loading situations. I have certainly seen couplers
between two cars that were "pulled down" from the
normal orientation when going thru a vertical curve.
Less possible movement in that direction under these
conditions would translate into more frequent break-in-
twos (but eliminate others).
And I'm sure that Kadee will tell you that if your
couplers are drooping that you need to look at how
they are installed and fix the problem that way. And
their argument is technically correct. However, it is
also true that installing a shim may be a much quicker
and easier way to fix the problem on a particular
installation.
One thing that I've seen done (and done myself) is
to reverse the copper spring in the box - to put the
'face' of it below instead of above the coupler. This
is one "quick and dirty" way to correct droop.


thomas christensen
 

--- In STMFC@yahoogroups.com, Denny Anspach <danspach@...> wrote:

The stated goal of this list is that "Emphasis is to be placed on
the study of the prototype with a goal of producing models of them
with as great a degree of accuracy as possible.


However, all manufacturers (less Sergent) are all hostage to the fact
that although coupler boxes are made to a rough standard (the old
original Athearn box of the late '50s),

Group,
Moloco has several coupler boxes that should be of interest to this group. They are detailed and appear semi-scale, although I have not yet seen them.
Tom Christensen


Denny Anspach <danspach@...>
 

The stated goal of this list is that "Emphasis is to be placed on
the study of the prototype with a goal of producing models of them
with as great a degree of accuracy as possible". To the extent
possible, that is also my goal on this thread.

There is not a single operational nor visual positive side to coupler
droop, and although I cannot speak for them, I will not believe that
Kadee, Sergent or Accurail (the only coupler manufacturers that I know
of who are actually thinking about such things, not merely producing
commodity knock-offs) would disagree.

However, all manufacturers (less Sergent) are all hostage to the fact
that although coupler boxes are made to a rough standard (the old
original Athearn box of the late '50s), in fact the coupler boxes can
vary considerably in depth, as do the thickness of coupler shanks.
The latter is even more variable when one considers that some coupler
shanks take into account the thickness of a sheet bronze centering
spring (even if the coupler does not need such a spring), while others
do not. As a result, the fact that any given coupler will in fact have
a smooth net fit in any given coupler box can be a crap shoot. The
Accumate Proto coupler is the exception (as I also believe the Sergent-
with-coupler-box) where the coupler and box are engineered as single
entity. As a result, they are the only couplers currently on the
market with no significant droop.

Shims can help, but required thicknesses can be surprisingly variable
(see above), and can also represent for the unwary modeler a lot of
pretty fiddly work.

We confuse operational practicality with prototype accuracy. They are
not the same thing.

As a matter of practicality or desperation, I may choose to (or HAVE
to) tow my freight cars with linked paper clips, loops of string, or
chewing gum around 9" horizontal and 45ยบ vertical curves, but it
surely would be a stretch for me to assert that has anything to do
with prototype modeling (except detraction) (:-).

Denny


Denny S. Anspach MD
Sacramento


Craig Zeni
 

On Feb 14, 2010, at 8:20 AM, STMFC@yahoogroups.com wrote:
3b. Re: Kadee Scale Coupler Operational Reliablity
Posted by: "Jim Betz" jimbetz@jimbetz.com oldrockygn
Date: Sat Feb 13, 2010 10:30 am ((PST))

Denny, et al,

While I agree that the standard length of the shanks on
the Kadee product line (and all other mfgrs as well - with the
possible exception of the Sergents) is longer than it should be -
it does mean that we can operate our model trains on track with
significantly more curvature than the prototype. The same can
be said of the width of the coupler box - and that measurement
is directly related to the same thing.

I have never seen a layout that has truly prototypical
curvature standards. And even those that have truly generous
standards (such as "nothing smaller than 36" on the mainline")
still have several areas on the layout that have smaller
curves and lower numbered turnouts. If I remember correctly
a #10 turnout -approaches- the typical smallest radius of the
prototype (and I'm not talking about mainline). Yes, of course,
these are generalizations/standard practices and you can go
out and find examples where the real RRs had more curvature
than these statements. But they are pretty close to what
the real RRs use as their standards (which they may or may
not break depending upon the situation).
On our layouts we 'fudge' even our own standards - not once
in a while but often/always. The phrase "I can make it fit if
I use a #4 turnout here for this industry track" is one I hear
a lot. The other thing you hear are statements such as "we
have 30-inch radius every where on our mainline - except for
the areas at _____ and _____" ... and those statements are made
proudly/as a brag about how generous that particular layout is.
And there is a real reason why the time-saver is based upon
all #4 turnouts.
If I remember correctly I think that an HO layout would
have to adopt s curvature standard of something approaching
that used on O-scale in order to be in the same ball park as
the real RRs.
http://www.youtube.com/watch?v=3IO0XYI8mew - my modular group. The curve the train passes on is 86" radius... 7'2"...and comparing it to main railroads it looks pretty tight. It's pretty sharp for us nowadays. Nothing tighter on the mainline except for the turnouts used to access the yards...which we detest but yards take up enough room without #18 turnouts leading in and out of them.

We use a mix of #5 and #58/158 couplers on our modular layout. If they match up to the Kadee gauge we have very little issue with random uncouplings in 80+ car trains running for 8 hours a day as moving scenery. Cars that uncouple or derail more than twice get lifted and inspected...usually finding a droopy coupler being the cause.



Craig Zeni
Join the Penn Central Railroad HS at www.PCRRHS.org


Dennis Storzek
 

--- In STMFC@yahoogroups.com, Tim O'Connor <timboconnor@...> wrote:

Denny,

Consider that most (uncushioned) model draft gear do not extend further
than the end sills, and then the extra shank length (.031) plus the smaller
coupler head means that the car-to-car distance is closer to prototype
than you might expect if you're only considering the shank length. So if
you insist on using only the "short" shank #153 then you must also mount
your draft gear so the distance over pulling faces of the couplers is
set according to the prototype.

Tim O'Connor
That's not a foregone conclusion, Tim. Back when I did the first kits for Accurail, I looked at this; my thought was to position the coupler pivot point so the cars had the correct coupled distance. What I found was that the coupler box would have to end back under the car, which was not going to please the customers. So, I just put the end of the box at the correct location of the striker plate, and figured some day our model couplers would finally catch up. From what I've seen, most manufacturers have done the same, modeling the car, but not paying much attention as to what the modeler is going to put in the coupler box.

Dennis


Jim Betz
 

Denny, et al,

While I agree that the standard length of the shanks on
the Kadee product line (and all other mfgrs as well - with the
possible exception of the Sergents) is longer than it should be -
it does mean that we can operate our model trains on track with
significantly more curvature than the prototype. The same can
be said of the width of the coupler box - and that measurement
is directly related to the same thing.

I have never seen a layout that has truly prototypical
curvature standards. And even those that have truly generous
standards (such as "nothing smaller than 36" on the mainline")
still have several areas on the layout that have smaller
curves and lower numbered turnouts. If I remember correctly
a #10 turnout -approaches- the typical smallest radius of the
prototype (and I'm not talking about mainline). Yes, of course,
these are generalizations/standard practices and you can go
out and find examples where the real RRs had more curvature
than these statements. But they are pretty close to what
the real RRs use as their standards (which they may or may
not break depending upon the situation).
On our layouts we 'fudge' even our own standards - not once
in a while but often/always. The phrase "I can make it fit if
I use a #4 turnout here for this industry track" is one I hear
a lot. The other thing you hear are statements such as "we
have 30-inch radius every where on our mainline - except for
the areas at _____ and _____" ... and those statements are made
proudly/as a brag about how generous that particular layout is.
And there is a real reason why the time-saver is based upon
all #4 turnouts.
If I remember correctly I think that an HO layout would
have to adopt s curvature standard of something approaching
that used on O-scale in order to be in the same ball park as
the real RRs.
I can't remember ever seeing a commercially available
turnout number larger than a #10. Even Fast Tracks only
goes up to a #12 (and I'll predict that they don't sell very
many of them!) - in HO and N ... and they only go up to a #6
in O-scale.

If you can get Kadee (or any other coupler mfgr) to answer
you I'm certain that you will find that the size of the coupler
box and the length of the shank has been chosen in order to
provide for operation of normal length equipment on tight
radius curves (where tight is defined as 22" or larger - at
least). The other thing that you will be told is that they
are using the sizes/measurements they are using due to the
NMRA standards/RPs.

Until we start to have layouts that do not compromise on
the curvature and turnout numbers in use I'm afraid we are
going to have to compromise on the coupler boxes and shanks.
I don't see any way around it.
I'll even go further and state that due to the sheer
number of layouts and existing model trains that are
already out there already you are going to be hard pressed
to figure out how to influence/change this reality. We may
be 'committed' to this state "for ever". *Sigh*
On the other side - I'm not sure any of us would ever
attempt to build a layout based upon true prototype
curvature standards ... we just don't have the space.

One last thing - all of the above relates directly to
the operational characteristics of our 'typical' trains and
is equally applicable to all scales and eras. If your layout
is early enough in the STMFC era that you have only 40'
or shorter freight cars then you might be able to use
smaller boxes and shorter shafts. Even a train of all
50' cars, going around a 40" radius curve - will look 'funny'
when compared to the real RRs. By 'funny' I mean that the
cars will be hanging out over the rail in the middle of the
car further than you will see them do on a real RR.
- Jim

P.S. It certainly -seems- to be true that having a coupler
box available that has a 'built-in shim' across the
opening to prevent coupler droop would be a good idea.
But I highly doubt we'll ever see it from Kadee - if
for no other reason than that it would prevent that
box from being used for a #5 with the existing copper
centering spring.
A good argument can be made for the idea that a
coupler "needs" to be able to 'droop' during certain
loading situations. I have certainly seen couplers
between two cars that were "pulled down" from the
normal orientation when going thru a vertical curve.
Less possible movement in that direction under these
conditions would translate into more frequent break-in-
twos (but eliminate others).
And I'm sure that Kadee will tell you that if your
couplers are drooping that you need to look at how
they are installed and fix the problem that way. And
their argument is technically correct. However, it is
also true that installing a shim may be a much quicker
and easier way to fix the problem on a particular
installation.
One thing that I've seen done (and done myself) is
to reverse the copper spring in the box - to put the
'face' of it below instead of above the coupler. This
is one "quick and dirty" way to correct droop.


Denny Anspach <danspach@...>
 

On Feb 13, 2010 Tim O'Connor wrote:

Consider that most (uncushioned) model draft gear do not extend further
than the end sills, and then the extra shank length (.031) plus the smaller
coupler head means that the car-to-car distance is closer to prototype
than you might expect if you're only considering the shank length. So if
you insist on using only the "short" shank #153 then you must also mount
your draft gear so the distance over pulling faces of the couplers is
set according to the prototype.
What is the scale relationship, i.e. distance, between the striker plates of coupled car, and/or what is the correct scale relationship, i.e. projected distance, between the face of the coupler box striker plate and the end sill on an individual car?

My opinion presumes that the coupler box striker plates are, or are placed in at least a close semblance of the correct prototype position, which IMHO they mostly are in the great majority of the fine models that the members of this list seems to embrace.

The Accumate Proto couplers are dead on, striker plate to striker plate, and the Kadee #153s are just two inches over- not enough to notice. This means that if the striker plates of the coupled cars have the correct relationship to their respective cars, then the use of these couplers will result in the coupled distance between the cars being at least very-close-to-prototype as well.

By the way, trains of fine prototype cars individually coupled at prototype distances apart can look stunning! ("Quality is the close attention to detail.).

DEnny


Denny S. Anspach, MD
Sacramento


Tim O'Connor
 

Denny Anspach wrote

That except for the short shank #153 semi scale couplers, the other
Kadee semi scale couplers (58, 78) are on prototypically excessively-
long shanks... Personally, I see no visual advantage at all to using
semi scale couplers of any variety unless the shanks are short...
Denny,

Consider that most (uncushioned) model draft gear do not extend further
than the end sills, and then the extra shank length (.031) plus the smaller
coupler head means that the car-to-car distance is closer to prototype
than you might expect if you're only considering the shank length. So if
you insist on using only the "short" shank #153 then you must also mount
your draft gear so the distance over pulling faces of the couplers is
set according to the prototype.

Tim O'Connor


Denny Anspach <danspach@...>
 

The operational coupling reliability level attained with the smaller couplers is determined by how accurately the couplers can be, and are centered/aligned at the moment when the couplers meet. The smaller gathering range of the smaller couplers reduces the room for error in this regard, requiring the operator choosing these couplers to pay even more attention to the biggest endemic culprit in the allowing of any given car to be off center: excessive axle/wheel-set end play. The usual excessive coupler shank length offers even more opportunity for poor centering.

Coupler droop is a big problem with any coupler using the standard "Athearn" or Kadee boxes, and IMHO is one of the biggest root problems with uncouplings/derailments, i.e. couplers pulled into distortion, allowing their draft angles to work into an over-ride; or more catastrophically, a coupler magnetic glad hand pulled down to snag the next closure rail. The droop in the proprietary #78 box is also excessive.

That except for the short shank #153 semi scale couplers, the other Kadee semi scale couplers (58, 78) are on prototypically excessively- long shanks. The weight of the heads sticking on the ends of these long lever arms do nothing but exacerbate the drooping problem. IMHO, from a prototypical point of view, seeing a coupler head sticking out like akin to a head on the end of a pole destroys any advantage that a small coupler head might otherwise provide. In this regard, if short shanks are not a choice, you are better off sticking to regular sized couplers, where the large heads pretty much hides the fact that the shank is too long, and that it is in fact sticking out of a grossly oversized coupler box.

Personally, I see no visual advantage at all to using semi scale couplers of any variety unless the shanks are short.

Denny


Denny S. Anspach MD
Sacramento


Scott Kremer
 

I use black sheet styrene, cut into narrow strips. It is obviously
smooth and you do not need to paint it unless the little bit of shine
bothers you. It is a good bearing surface. As Brian indicated .005 or
.010 works fine. I do this on almost all of my cars. I find that even
when the coupler looks fine on its own it will sometimes "droop'" if it
is under stress as in a heavy train. Just glue it to the coupler pocket
under the coupler shank at the front edge of the pocket.

Scott Kremer

On Feb 11, 2010, at 6:12 PM, Brian Carlson wrote:



Like Tim said: I use strip stryene, usually 0.010, or 0.005 as
required, fit to lip, glue, no droop. I don't like using the spring
material it's easier for me to glue plastic to plastic but YMMV. If
you need a strip thicker than 0.010 you have bigger issues like a
loose box, or angled one.
Brian Carlson

At 2/11/2010 01:08 PM Thursday, you wrote:

>Brian, I assume you are making the .005 shims. Can you describe
them? ...material used, how you make them, do they go above or below
the coupler?
>
>Thanks,
>Tony Higgins
>Pittsford, NY




Brian Carlson
 

Like Tim said: I use strip stryene, usually 0.010, or 0.005 as required, fit to lip, glue, no droop. I don't like using the spring material it's easier for me to glue plastic to plastic but YMMV. If you need a strip thicker than 0.010 you have bigger issues like a loose box, or angled one.
Brian Carlson

At 2/11/2010 01:08 PM Thursday, you wrote:

Brian, I assume you are making the .005 shims. Can you describe them? ...material used, how you make them, do they go above or below the coupler?

Thanks,
Tony Higgins
Pittsford, NY







[Non-text portions of this message have been removed]


Tim O'Connor
 

Tony, you can use a piece of strip styrene of whatever thickness
you desire to correct droop when the coupler droops within the
pocket. You glue the strip (i.e. shim) at the open edge of the
pocket, so the shank of the coupler is lifted upwards. A little
experiment will show how much shim you need. Note this is only
for coupler droop -- if the pocket is too low, then you need
another solution. Obviously you glue below the coupler -- I've
never seen a Kadee coupler droop upwards. (Pocket tilt is a
different problem.)

Tim O'Connor

At 2/11/2010 01:08 PM Thursday, you wrote:

Brian, I assume you are making the .005 shims. Can you describe them? ...material used, how you make them, do they go above or below the coupler?

Thanks,
Tony Higgins
Pittsford, NY