An N-Possible journal

[mu26aeh]

A side note with the DODX cars, the cars I have the wheels rub the underside of the car causing considerable drag.  Do yours, or anyone elses do this ?

[BCR 570]

This is also an issue with the Rapido Trains/Prairie Shadows gondolas.

Tim

[samusi01]

A side note with the DODX cars, the cars I have the wheels rub the underside of the car causing considerable drag.  Do yours, or anyone elses do this ?

The 41XXX (four axle) are better than the 40XXX (six axle) for me... I've got ExactRail 36" in mine. If you have any spare ESM 36" wheelsets give them a try.

[GaryHinshaw]

One of these:
https://www.busybeetools.com/products/1in-belt-sander-craftex-cx-series

Interesting, thanks.  Hold on tight to that part!

RE tolerances: I don't want to leave anyone with the wrong impression.  I find I have no trouble centering a scale box to within ~10% of its width by eye, and that is tighter than the typical lateral play in a factory car.  Before I put a converted car on the layout, it must pass a coupling test with the standards gauge: if it won't couple to the gauge after two attempts, it gets re-worked, but that is rarely required.  If it doesn't couple the first time, it is almost always due to truck/wheel issues: the bolster pin is too narrow, the axles are too short, the wheels are under-gauge, etc.), and nudging the car a bit makes it couple the second time.   If it doesn't couple the second time, it often points to a faulty installation: usually either an over-tight shank or to 'extreme' slop in the trucks/wheels.

In my experience on the layout (now with ~400 conversions completed and many hours of running), I get something like 90% coupling efficiency on the first try and 99+% efficiency after two tries.  I am very happy with that!  Even better, the performance of a coupled train on the layout is outstanding: no more spontaneous un-couplings (super important on Tehachapi), no more slinky, and pusher operations are much more reliable.

I am still in my first pass through on converting the fleet, so I am still focussed on quantity+quality.  I plan a second pass that will be focussed on weathering+quality.  Some cars may get re-tuned at that stage, but relatively few as far as I can tell now.

[Jimbo]

BLI Mikado - PILOT only

I successfully installed a short-shank N-Possible coupler using a modified scalebox to the pilot of one of my BLI Mikados.

I held off on performing an installation on the tender, due to the need to do some grinding to ensure proper clearance.  I am not enthusiastic about doing this, as it will likely require me to disassemble the tender to ensure that the locomotive mechanism and the decoder are far away from any flying debris from the grinding process!

Step 1:  Remove the existing coupler.  This is easy; simply remove the screw.  The screw has a small boss that also serves as the post.  You will re-use the screw, but not the boss.



Step 2:  Prepare the scalebox.  You will be using the BOTTOM of the scalebox.  The scalebox will need to be shortened...  almost to the post.  I used trial and error to get it the right length.  Additionally, you will need to file the center post down slightly.  (There's a step in the post that aligns with the hole in the scalebox lid.  Remove that step, plus just a wee bit more.)



Step 3:  Install the short shank coupler (scalebox version).  Assemble the short-shank coupler and install it in through the front.  There is a ridge around the screw hole that you'll have to work around; be careful not to mangle the coupler spring in the process!  Take your time.  I used a wooden toothpick to massage the spring over the ridge.  As you can see, the spring got just a bit wonky, but the coupler still works as designed.  It is because this ridge is there that the screw does not protrude all the way thorough the pilot, and is also the reason you need to take a couple of thousandths off of the center post.



Step 4:  Install the modified scalebox and screw in place.  NOTE:  Getting the modified scalebox properly aligned with the spring splitter in the correct location is tricky.  I used a toothpick to align everything; once the spring splitter is properly in place relative to the spring, it's then just a matter of getting the coupler properly aligned.  At this point, you can use the original screw to tighen everything down.



Step 5:  Verify the height.  Mine was dead-on.



A few notes:  My first instinct was to use the Universal mount.  However, once I installed the metal spring splitter, the clearances were such that I was unable to install the coupler through the front.  So I started over using a procedure I used for the Bachmann Alco 2-6-0.  I have become a fan of the scalebox and the versatility of its design, as it's easily modified for unique applications such as this.  Another thing to note is that this is not a simple coversion; I would not recommend it for someone just starting out.

Hope this is useful to others; please let me know if this format for describing the procedures I've used for these unique installs is clear; I'm open to any suggested changes for future guides.

Respectfully,
Jim

[thumpernickle]

I am looking for some thoughts on a conversion I would like to attempt.
I have a brass Precision Scale N Scale Southern Pacific steel cupola caboose I would like to convert to N--Possible. It has a coupler box as shown here:
and here


The coupler box was designed for a MT coupler, probably the 1015. I haven't check.

An unmodified SBX sits too low, which I am slowing shimming up and believe I will get to the correct height.

My concern is clearance for the movement of the coupler spring. I believe the width (meaning rail to rail side) is ok, but the brass coupler box is not long (or deep) enough. Hopefully the picture helps.


I have never done any type of modification of my few brass models, and am hesitant to cut them if I don't have too. Any thoughts or suggestions?

[garethashenden]

I am looking for some thoughts on a conversion I would like to attempt.
I have a brass Precision Scale N Scale Southern Pacific steel cupola caboose I would like to convert to N--Possible. It has a coupler box as shown here:
and here


The coupler box was designed for a MT coupler, probably the 1015. I haven't check.

An unmodified SBX sits too low, which I am slowing shimming up and believe I will get to the correct height.

My concern is clearance for the movement of the coupler spring. I believe the width (meaning rail to rail side) is ok, but the brass coupler box is not long (or deep) enough. Hopefully the picture helps.


I have never done any type of modification of my few brass models, and am hesitant to cut them if I don't have too. Any thoughts or suggestions?

That looks like the coupler is supposed to slide into the box and be held by the screw. Probably a 1023. Can the ScaleBox fit inside that coupler box?

[thumpernickle]

That looks like the coupler is supposed to slide into the box and be held by the screw. Probably a 1023. Can the ScaleBox fit inside that coupler box?

The scale box (SBX) does slide into the brass coupler box without problem. My question is about the clearance at the back of the brass coupler box. I think the coupler/spring area of the N-Possible coupler prevents the coupler from operating correctly by preventing it from fully swinging from side to side.

I guess my question is: How much clearance is needed at the back end of the N-Possible coupler for smooth operation?

[Sokramiketes]

So the brass box has a back on it, right?  It looks like there's clearance to use a Dremel with a cut off disc to cut off the back of the box.  (If you're brave).

If it were mine, I'd also consider just prying off the whole box and leaving it open.  You'd be surprised how weak most solder joints are on these brass models.  Depends how important it is for you to keep it stock!

[thumpernickle]

So the brass box has a back on it, right?  It looks like there's clearance to use a Dremel with a cut off disc to cut off the back of the box.  (If you're brave).

If it were mine, I'd also consider just prying off the whole box and leaving it open.  You'd be surprised how weak most solder joints are on these brass models.  Depends how important it is for you to keep it stock!

Correct, there is a back to the brass coupler box. I think I am brave enough to try cutting the back of the box off.

I have considered removing the brass box completely, but the screw hole is only in the bottom of the box. It is threaded to hold the screw in place and forms a post for the center of the actual coupler. There is no hole on the opposite side of the box, into the porch of the caboose. At this time I have ruled out drilling a hole into the porch of the caboose.

[Sokramiketes]

Makes sense!  Leave the box so the screw can thread in, which is good.  And no screw up through the porch, also good.  You're next step will be to keep the scalebox from spinning, if it's not a tight fit already.  I'd be inclined to just do a drop of superglue to hold the box centered. 

[brill27mcb]

I would try to drill out the rear wall of the brass coupler box, with the drill bit entering from the open front of the box. Then I would use jeweler's files, going in the same way, to "square up" the drilled opening in the back wall to make it just wide enough to fit the back of the N-Possible box. That would hold the N-Possible box from rotating inside the brass box. No glue needed, and all the work would be inside the coupler box, keeping visible paint intact.

Rich K.

[GaryHinshaw]

Scale Trains Multi-max auto rack  (see also the postscript below.)

This is one of those cars that has been sitting on the to-do bench for months now, but I think I have a conversion I'm finally happy with.   I wanted to both lower the ride height and get a coupler conversion that performed well and didn't require too much surgery. 



This story is best told in photos, so here we go.  The stock model has a pocket that is a bit short, and many of my samples had a post that was splitting from the screw that holds the lid.  The combination would cause the N-P coupler to bind:



The top side of the stock box shows how it is molded in to the floor:



If you don't mind the ride height you can probably get away with a straight URS conversion, but you'll probably have to file the lid down a bit (and maybe deal with a split post) to get good coupler swing.  You'll probably end up with a slightly low coupler though.  In my case, I wanted to lower the ride height to more or less match the height of the Red Caboose racks (per the prototype), which necessitated modifying the coupler mounting.  The solution I settled on turned out to be pretty straightforward: first file down the bolster pad on the stock truck so it is basically even with the truck's cross member (filed on the left, stock on the right; and sorry, best photo I could get):



(I also swapped in Fox Valley 2802 wheels.)  Next, replace the 'roof' of the stock box with a piece of styrene.  This requires cutting out the stock floor with a knife (score around the base with a #11 blade, then finish it with a single edge blade and a bit of filing to dress it):







Glue a new roof from a piece of 0.060 x 0.250" styrene stock:





Mount a scale box with short or medium shank to the new roof (I used a short shank):



The resulting coupler height is a tiny bit low, but the coupler performance with the scale box is great:





The ride height is better:





Now to do about 10 more of these... then decide how I want to handle the Red Caboose cars.  But the ST cars are awfully nice models.

[Sokramiketes]

I would try to drill out the rear wall of the brass coupler box, with the drill bit entering from the open front of the box. Then I would use jeweler's files, going in the same way, to "square up" the drilled opening in the back wall to make it just wide enough to fit the back of the N-Possible box. That would hold the N-Possible box from rotating inside the brass box. No glue needed, and all the work would be inside the coupler box, keeping visible paint intact.

Rich K.

Nice idea, but the nPossible needs movement at the back of the box.  So restraining it there will limit the swing of the couplers.  There arn't box sides back that far on the scalebox for that reason. 

[ednadolski]

But the ST cars are awfully nice models.

You're almost making me regret getting rid of the bulk of my N scale fleet  😢

Ed