Experience with American Limited diaphragms

[Hazuki]

Has anyone installed American Limited diaphragms on Kato smoothside passenger cars?
I read in a picture of the instructions that the minimum radius is 20". Is that correct? In my staging yard I only have 15".
I would be grateful for any experience reports.

[DRGW5349]

Yes, I have installed many on Kato and other manufacturer cars. You will need around 20" radius if you keep the Kato trucks. This can be reduced to around 12" by using Micro-Trains 1017 style trucks with an adjustable coupler. By moving the coupler farther out, you create more distance between the cars, allowing for a tighter radius curve.  In the end I found that the distance between the cars needed was too great and the train as whole did not look right. Also, the detail on the stock Kato diaphragms looks better, so I ended up keeping most of my Kato cars unmodified.

[peteski]

I'm not a fan of how those add-on diaphragms look in the models.  They are out of scale and too bulky, but I guess there are compromises to  be made if one wants to close up the gap between cars.  I prefer the small visible  gap with the stock Kato diaphragms.  We all see the world a little differently.

[randgust]

Two things happen, one is they are too tight, and the second thing is that they can snag against each other.

You can solve the snagging problem by gluing a thin piece of clear acetate on the face, they'll slide right by each other then.  That happens if you're running through a crossover with any turnout #6 or tighter.   If your curves are spiraled they won't snag bad there.

I've also deliberately 'stressed out' the spring so that they don't push hardly at all; get that magic .010 clearance between two cars under tension.

Centralia (intermountain) passenger cars use them.

In the old days I'd folded up black and dark gray paper like an accordion between cars, that was amazingly effective visually, didn't snag, you could set the tension very, very light, and deal with 11" curves too.

[thomasjmdavis]

My experience is similar to what has already been said.  But to answer the specific question-

On my last layout,  I had 15" minimum radius with easements- and the cars I had equipped with ALM diaphragms did not operate well, even at slow speeds.  These cars were not Kato branded, most were built from sides with ALM core kits or were Centralia, but of similar length.

As Peteski notes, the Kato cars look pretty good as is, and I left mine alone.  That could change if I ever get the next layout off the ground, with planned 24" minimum radius. 

I had some luck operating ONE ALM equipped car with Kato trucks/couplers fitted (a lunch counter diner that met with a cruel fate later on), in between 2 factory equipped cars . But even then there were unacceptable number of derailments with the ALM diaphragm hanging up every once in a while.

[eja]

I have on occasion put a diaphragm on only one end of the car.  Fills the open space nicely and from a few feet away, it is not noticeable that there is only one rather than two between cars.  Certainly helps the radius issue.

eja

 

[bbussey]

I’ve used them and liked them for years, and also 3D-printed diaphragms based on the ALM design. But my minimum radius is 18” in reverse loops.

[Sokramiketes]

Just to add one more data point, the original Modutrak end loops were 19" radius as that seemed to be the minimum for diaphragms and body mounted Z scale couplers to work. 

You get a little more side to side swing on an N scale MTL coupler.  So I'm sure 18" could work there.  Less is getting tricky. 

[nkalanaga]

I tried them on my core-kit equipped cars.  As others have said, snagging was a problem, and they don't like #6 crossovers.  I ended up leaving them on, but gluing the two pieces together with white glue.  They ended up looking like Kato diaphragms from the side.  Might as well buy a bag of Kato diaphragms!

If you have wider curves, and longer turnouts, especially with easements on the curves, they'll probably work fine.  But my 18 inch curves were just a little too much, and the one 17 inch didn't work at all.

Like Randgust, many years ago I made diaphragms from folded paper, and they worked quite well. 

[Hazuki]

Thank you for all the feedback. I will stick with the original ones from Kato.
The question for the change arose primarily because I want to convert a COLA set to Excursion operation. I will now order the modern diaphragms from Kato.

[dem34]

Wish more companies offered something like the Atlas Shorties do where each pack of cars included flexible rubber diaphrams that friction fit into the door openings. Looks nicer than the gap and still navigated 11" curves.

[thomasjmdavis]

Wish more companies offered something like the Atlas Shorties do where each pack of cars included flexible rubber diaphrams that friction fit into the door openings. Looks nicer than the gap and still navigated 11" curves.

I'd be happy if Atlas just offered those in 12 packs (or larger).  The diaphragms are one of the plusses of the Atlas cars.  And they make them in 2 sizes, with both sizes included with the car (at least, that was the case with the first run cars I purchased), so you can adjust for wider or narrower coupled spacing, as your preference and/or radii allow.  I have several projects just waiting for Atlas to make parts available for those cars.