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The information below is captured by Jeff Saxton from various email discussion on
the Sn2_Trains email list at yahoogroups.
The Sn2 Coupler FAQ; compiled by Dave Keith
The following standard has been developed through extensive list discussions
occurring over a several month period of time.
The members of this list have adopted a standard for Maine 2-foot modeling.
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Coupler: Kadee HOn3 #714 or HO "Old Time" #711 couplers, with the trip pins snipped off.
- Body Mount Height: 18" in S scale = 9/32" actual.
- Coupler Centerline Height: 14.5" in S scale = .226" actual.
This is derived from mounting the #714 couplers at the required
BODY height.
Why the HOn3 (#714) or HO Old Time (#711) coupler? The knuckles
of the #714 and #711 couplers are the closest to the size of an
S scale Maine 2-foot coupler. HO and N scale couplers are either
too big or too small (more information pertaining to the HO and N
couplers below)
For all remaining answers in the FAQ, I will use HOn3 or #714
when referring to the couplers. The #714 and #711 are the same
size, the only difference is the trip pins.
How did you get 18" for the body height? Most of the freight
cars on the Maine 2-foot railroads have an 18" body (sill)
height from the railhead. There were some exceptions, but
18" seemed to be the most common height.
Most Maine 2-footers had a coupler height of 16" (to coupler
centerline), so isn't 14.5" too low? Yes, 14.5" is too low.
However, a compromise had to be made because the mounting
box of the HOn3 coupler is thicker than that of a real
2-foot coupler. The HOn3 coupler is 3.5" from box top
to center of coupler, but the prototype couplers were
only 2".
Therefore, one of 3 compromises had to be made:
- Raise the body height
- Recess the couplers into the body
- Have lower couplers
For esthetics and simplicity to build, we chose to compromise
coupler height. This way the car will ride at a prototypical
height and have the couplers mounted on the bottom of the
body like the prototype.
Why are the trip pins clipped off? Because we mount the Kadee
couplers lower than the NMRA standard for HOn3, and as such,
the trip pins would hit the rails when going through a turnout.
We plan to uncouple cars manually not magnetically.
Why wasn't the HOn3 standard used for coupler heights? The
HOn3 coupler height equals 18" (to centerline) in S scale.
Thus, it is too high for Maine 2-foot equipment. If we
adopted the HOn3 coupler height, then the car bodies would
have to ride high, or the couplers would have to be recessed
into the endbeam of the car. The HOn3 coupler height gauge
may be correct for prototypes other than the Maine 2-footers.
The HOn30 folks chose the N scale coupler height, even though
the N scale height is not right for HOn30 models of Maine
2-foot equipment. Thus HOn30 models have compromises that
we did not want to have in Sn2.
What about Passenger cars? Most 2-foot passenger cars had body
heights greater than 18". More like 20" or 22". Thus they had
a special mounting for couplers under the end platform. Sn2
models of Maine 2-foot equipment will have to have a similar
mounting.
What about Locomotives? There are issues here that we have not
yet addressed, as we do not yet have brass locomotives. We feel
these will become easy to address once we have commercial
locomotives; but for now, anyone building locomotives and
mounting couplers should follow the above standards.
What about 2-footers outside of Maine? Gilpin? Wales? The
Industrials? The standard presented here is for Maine 2-foot
equipment. It does not apply to other railroads. The Gilpin
(in Colorado) used link & pin couplers mounted on the ends of
the cars. I think many industrial railroads would have done
likewise. One member of this group has chosen the HOn3
standard of 18" for his Gilpin models. This is probably a
reasonable compromise considering the Gilpin did not use
knuckle couplers. The Gilpin cars had body heights from 20"
to 27". If the HOn3 couplers are mounted on the bottoms of
the cars at the 18" height, then that means the bodies are
21.5", and that is in the range of the prototypes.
What if I model a free-lanced railroad outside of Maine?
Some of the members of this list are placing their 2-foot
railroads outside the state of Maine. However, most are
still inspired by the Maine 2-footers so they are opting
for this standard as well.
Why an Sn2 standard at all? How many Sn2 modelers are there?
Currently, the Sn2 segment of the market is small. But this
group hopes that Sn2 will grow enough to support Sn2 products
such as cars, locomotives and structures. We already have
true Maine 2-foot trucks. Thus, we need a standard for
manufacturers. Additionally, we may want to run models
together or have a module meet. At such times a coupler
standard will ensure that trains will stay coupled.
2/20/2005
Addendum to Coupler FAQ. After several more exchanges
on the various other makes and brands of couplers that may
be possible to use in Sn2, we have updated the FAQ.
Compiled by Jeff Saxton.
Kadee (Micro-Trains) N Scale Couplers:
Here are some thoughts on use of n-scale couplers
- Pro: Come pre-assembled
- Pro: Smaller, no interference for Sn2 equipment
- Pro: Can be used with magnets at Maine 2-Foot prototype height
(#714 cannot do this)
- Pro: Compatible with 714 (they couple reliably)
- Con: Actually too small for Sn2
- Con: Does not couple on curves as well as #714
- Con: Requires tighter (more exacting) standards for coupler height,
not as much forgiveness as #714
Because the N-scale couplers mate reliably with #714
couplers, they are a viable substitute for tight situations where a #714
might not fit. A #714 can be trimmed at the rear, but should that
not be enough, an N-scale coupler may be the best choice. Examples
usage might be a short wheelbase car or a locomotive pilot. If an
N-scale coupler is used on Sn2 rolling stock, it should be mounted
according to the coupler center height requirement.
Accumate HO "Scale" #1020 Couplers:
These "Scale" HO couplers are a good match in size for S-scale
3/4 couplers used on many narrow gauge railroads, but the #1020
coupler box needs to be modified. The #1020 uses a box which is
narrower and should fit inside an HO standard gauge coupler box.
They should adequately fit the narrower width confines of Sn2
with some shaving if one is concerned.
The 1020 couplers include a paper which essentially says
(paraphrased): "when cut back in length to the internal
bulkhead, they match the size of boxes from other commercial
HOn3 coupler makers". This almost has to refer to Kadee #714
couplers.
Pro: Closer to actual S Scale size.
Con: Online purchasing is the only real option for these.
Con: Mounting boxes need to be re-worked before use.
Sergent HO "Scale" Couplers:
The HO Sergent is designed to fit into a standard "#5" box as
supplied with most HO kits. It is possible to mount them
without any box at all by simply using a screw.
There are two primary problems with either the Sergents,
Accumate or other brands mentioned. The first is that they
are harder to find, and from smaller firms that may not even
be around in ten or fifteen years (we think Kadee will be with
us for some time yet). We have serious doubts that Sergents
or Accumate will still be a viable production item in twenty
years.
The second problem, especially in terms of these "off-brand"
couplers, is the added work required to assemble them, and get
them mounted, and then operating properly. Kadees, while not
optimal, certainly are much more of a 'brainless' assembly and
installation process, with less problems in designing new mounts
for each new product as it comes along. There is also the added
track record of a firm long in business, with replacement and
repair parts as close as your nearest hobby dealer.
Kadee #58 or #78 "Scale" Couplers:
The #58 coupler box is far too wide to fit between the wheelsets
of an Sn2 freight car. The #78 has a much narrower box. This
subject was discussed on the HOn3 list previously, and while more
than one person came forward and said that the #78 "worked" for
HOn3 cars because the coupler box was small enough (they had tried
it), Jeff Bissonette later noted that the #78 box is still too big.
It won't allow sufficient truck swing on cars where the distance
from the end sill to the centerline of the bolster is 3' 9" or
less, and it will foul the outer axle.
Another downside of the #78, is that they only come assembled
(more expensive) and not all hobby shops carry them on a regular
basis.
The problem with any Kadee HO couplers will still boil down to the
coupler box itself, since that box is still the same basic item as
used in the #5 Kadee coupler. The size of the box limits rotation
of trucks on freight cars.
Link and Pin Couplers:
Grandt Line makes an On2 Gilpin Tram link and pin
coupler set in plastic that is acceptable. Not
perfect, but usable.
Alexander HO Sclae Link & Pin. They are too large
for HO but will work for S Scale. They require a
coupler box the same size as a Kadee #4 and use that
style mounting. They might be able to be screwed to
a car with no box at all. Does anyone have current
contact information for Alexander Scale Models?
The Back Shop is now offering an On3 Link & Pin that
drops into a standard KD #5 box.
Russ Simpson makes a West Side Link & Pin in On3 that
is small and Mac Neil (available from Coronado Scale
Models) makes a brass Gilpin On2 unit that is also
very small.
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