An N-Possible journal

[GaryHinshaw]

Gary, don't suppose you have a Z scale car you can do a test installation on?

No.*   

Man, These couplers, and the simplicity of install are tempting......
Do I really want to convert everything I have though. 

Yes. 

* But if you'd like to send me one, I'll try converting it for you.  I do note that the AZL couplers are compatible with the N-Ps, so you don't have to commit en masse.  (The Full Throttle couplers are not compatible though.)

[GaryHinshaw]

A Tale of Two TILX.  Here are two covered hopper conversions, both PD hoppers from Atlas (nee BLMA for the 5660) but with very different stories.   



The larger 5660 cuft hopper is one of the finest cars in N scale, the smaller 3230 cuft hopper - not so much.  I'll start with the easier 5660 conversion: the coupler pocket and truck post is a separate part that is glued to the car.  I first tried a retro-fit into the existing pocket, but the coupler height was too low, and it required carving some room in the back of the pocket to accommodate the centering spring.  It turned out to be much easier to remove the pocket outright and use a scale box.  To remove the pocket, make a cut right behind the pocket wall with a razor saw:



Pry the pocket off with a chisel-point X-acto blade (it does not take much force to break the bond):



Mark the position for a mounting screw:



Use the screw as a tap to prep the hole:



And that's it:



The coupler height is perfect without having to raise the ride height.

The 3230 pocket is cast as part of the car, so a scale box is not an easy option.  Alas the stock pocket is too short to accommodate an N-P without modification.  Since some tricky surgery was required, I first made a cradle to protect the somewhat fragile roof walk from damage.  I used 1/8" square and 1/8" x 1/4" styrene as shown:



For the pocket modification, I made two cuts with a razor saw: one on either side of the rear box wall:



Use a sharp narrow X-acto blade to carve out the required material, down to the level of the box "floor" (actually its ceiling):



Glue the retro-fit centering shim into the box:



Install the coupler:



I had to draw up and print a new pocket lid for this car because the existing lid was binding the coupler slightly (unless I left the screw quite loose):



In addition to the above, I cleaned up a lot of assembly and finish issues with the car (personal preference) and I swapped out the ugly wheels for FVM 3603 wheels, which - despite having an axle length of 0.563" - are actually a bit shorter than the stock wheels, which are the longest axle I've ever seen in N scale at 0.574".  The FVM wheels work well though.   Finally, I added some 0.2 mm washers on either side of the truck bolster (2 per bolster pin) to raise the ride and coupler height slightly, and to stabilize the otherwise wobbly gait these cars have.   

In the end, I'm very happy with both conversions, giving cars that look great and perform very well:



The box lid and washer parts may be downloaded here.

[GaryHinshaw]

Two IM Trinity hoppers.  These two conversions (the 3281 2-bay and the 5161 3-bay hopper) are straightforward scale box installs.  The trick is getting the correct coupler height and a decent ride height without resorting to significant surgery (and also dealing with the shaky Intermountain quality control).



For the 3281, I just swapped out the stock body-mount coupler for a scale box install with a medium length shank:



The medium shank looks a bit out of place, but a short shank would make the car spacing too short unless the box were moved out.  But that would require filling the existing screw hole and drilling a new one ~1 hole diameter further out.   Too much work and risk.  The medium shank will look better when I add a crossover to the car.  The wheels were swapped out for FVM 3602's, and I replaced the clear washers with a 0.2 or 0.3 mm printed washer, as required to tune the coupler height.  I also replaced the crazy stirrups and fixed some issues with the end cage assembly, as detailed elsewhere.

For the 5161, I drilled a screw hole in the outer indent of the centre sill:



and installed a scale box with a short shank coupler:



I replaced the stock MTL trucks with BLMA 100T/36" and added a 0.5-0.6 mm washer as required to tune the coupler height.  (I will also be replacing the stirrups and adding crossovers eventually.)

A note on ride height.   The 5161 with BLMA 100T trucks and 36" wheels with an MTL 0.5 mm washer is a good match to the Scale Trains 5188 hopper, which it often shares a grain train with.  From left to right below: a 5188 (more on that conversion later), a converted 5161, and a stock 5161 out of the box:



The ST and the converted IM line up very nicely.  The stock IM rides a bit high.

[Sokramiketes]

Back to your question on painting and weathering, it’s another place where these shine. They are not engineering plastic, therefore take an application of paint or powders really well. And they at least need a dusting of powder to really highlight the detail put into the parts.

Like this:

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Paint should be applied by airbrush after assembly. Keep those surfaces lubed with the soft pencil.

[Sokramiketes]

To add to what Gary is sharing, I’m also using the suggested 10B soft lead pencil on the coupler components. I do this after touching up the support nubs with a 600 grit sanding stick.

Rest is the same, but I’ve had to be a more fastidious modeler than I’ve been in the past, at least with drilling mounting holes. I’ve eyeballed for years and gotten away with it on MTL legacy couplers. But now I’m printing drilling jigs.

Here’s a quick example on a unit train of Athearn (ex MDC) high side Thrall gondolas.

It has a tapping block style nub to help drill square to the carbody as well.
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This example was mounted then dusted with AIM “dark earth” weathering powder. Besides helping with prototype appearance, it also aids uncoupling visibility.
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You can mount the airhose after dusting if you want to keep the hose looking fresh. I touch it with a silver sharpie and call it a day.
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[GaryHinshaw]

Excellent Mike.  I added your example to the index in the OP. 

I should weather as I go, but I have several ops sessions coming up and I'm trying to sprint through as many conversions as I can this summer.  But I can confirm that powders do adhere well to these 3-d prints in a few of the experiments I have done, and the couplers really do pop with that treatment.

BTW, I have not found it necessary to lube the parts with a pencil.  Mine have been working really well without it; but I'm sure it can't hurt.

[Olivani]

When can I order them ? When will they be available for not so VIP ?

[Missaberoad]

When can I order them ? When will they be available for not so VIP ?

https://www.cvrco.ca/CVSearch/default.aspx?Manufacturer=517&start=B517-101SBXK&end=B517-301URSK

[basementcalling]

Gary, you attention to detail is phenomenal. Excellent thread.

I probably will not convert all my fleet over, but newer cars are definitely going to get these for the next layout.

[Ed Kapuscinski]

Gary, you attention to detail is phenomenal. Excellent thread.

I probably will not convert all my fleet over, but newer cars are definitely going to get these for the next layout.

And in the meantime, if you don't want to mess with conversion cars, there's this: https://conrail1285.com/solving-the-backwards-compatibility-problem-with-n-possible-couplers/

Gary, this is incredible. I'll start porting it over to the actual site shortly.

[NtheBasement]

Seems like the body mount install requires a lot of skill and precision.  Is there a way to slide an Npossible into an existing MTL coupler box if I surgically remove the MTL's center post?  Or maybe slide off the MTL coupler top and replace it with a printed Npossible-compatible box part?

[learmoia]

When your doing the 1015 retrofit conversions, how often is it an issue to cut way from the back of the box to clear the spring?

[Jbub]

Seems like the body mount install requires a lot of skill and precision.  Is there a way to slide an Npossible into an existing MTL coupler box if I surgically remove the MTL's center post?  Or maybe slide off the MTL coupler top and replace it with a printed Npossible-compatible box part?

There is a universal N-Possible coupler just for this application.
https://www.n-possible.com/resources/urs-assembly-instructions

[turbowhiz]

Conversions are an art; And there is often more than one approach that can be taken for any given scenario.

Some approaches and techniques that work well for one person are not accessible or comfortable for others. We all have different priorities too, so what is important for one might not be for another.

Gary has been removing “1015” type boxes from models entirely and replacing them with scaleboxs in circumstances I’d not considered. This approach has real advantages: The scalebox looks way better than the oversize OEM boxes, and the coupler works reliably with no tuning or compromise in the scalebox. He’s also addressing coupler height issues without compromising the overall ride height of the model. I’m going to replicate his approach myself from time to time.

But some might find that approach more complex than using a URS in the OEM box, and potentially adding some washers to sort a low height issue.

On the 3820’s, I’ve not had binding problems with the oem lid. Or at least not after either filing the lid a hint/and or removing the retainer/thumb shank ring. And my approach to finding space, namely a fine burr on a rotary tool is faster/easier for me personally then Gary’s approach. But there is no right/wrong way, and what works well for one might not work well for another.

In terms of OEM boxes needing space, it really depends on the composition of specific models you have. ScaleTrains don’t need extra space, Tangent hoppers didn’t, most Atlas/BLMA does but not spine cars, Athearn doesn’t but the Acid tanks do…. MTL mostly needs space but the PS-2 hoppers don’t. Its hit and miss, I’ll advocate for OEMs to ensure it exists in future designs but given the fact that MTL pin slots were never standardized I’m not counting on much there.

[GaryHinshaw]

When your doing the 1015 retrofit conversions, how often is it an issue to cut way from the back of the box to clear the spring?

I'm not quite sure what you mean by "1015 retrofit conversion" but it is worth emphasizing that an N-P shank is a drop-in-place substitute for an MTL coupler in a genuine 1015 box:





Here is an example of a stock box without room for the centering spring in the back (this is the Aurora Plate F box car):



It wouldn't be too hard to modify this box to accommodate the spring, but happily this box is easily removed and replaced with a scale box, so it's not necessary.  I don't have a detailed census of cars that require surgery to convert, but I am hoping to document a bunch of the modern ones (at least) here.

Conversions are an art; And there is often more than one approach that can be taken for any given scenario.

Some approaches and techniques that work well for one person are not accessible or comfortable for others. We all have different priorities too, so what is important for one might not be for another.

Absolutely!  My main reason for these posts is to document my conversions for my future self, so I can remember what I did.  I don't intend for my approach to be unique or definitive.  I do hope they're useful though.  And I am super grateful that Andrew had the vision and fortitude to bring this product to market!  The improvement in appearance and performance is transformative.