Is Finetrack not to N gauge standards?

[David]

I was checking the wheel gauge of some locos with the Microtrains gauge tool when I set it down on some Finetrack I've been testing with - and it wouldn't sit (there are little feet meant to match up with the inside of the rails so that it sits at an exact height and centering). I turned the tool on it's side and used the little track gauge check and the same thing - the rails where about 1/3 to 1/2mm to close together, you could not get them into the notches of the gauge. I tried several other pieces of Finetrack to be sure, then I got out the Kato blue rerailer, which has rail gauges cut into the side and got the same result. To make sure I hadn't forgotten how to use the gauges I pulled some Unitrack and Model Power sectional track and both tested easily.

 

Is there a reason why Finetrack seems to be 8.6mm instead of 9mm?

[bill937ca]

It wouldn't surprise me because Japanese manufacturers have their own little world.  But if it was that different from Kato Unitrack you wouldn't be able to run N gauge trains on either Finetrack or Unitrack like we all do.

[Martijn Meerts]

Not sure if it's a coincidence or not, but I was running my EF65 on my father's layout today. The layout uses Minitrix and Roco track, and I noticed that the EF65 has a LOT of problems with the larger radius curved turnouts. Where the blades of the moving part hits the stock rail, there's a little notch. The blades fall into that notch. The problem is, the wheels of the EF65 also fall into that notch.

 

The Minitrix locomotives I've tested have no issue at all, so I'm expecting the EF65's wheels are close together, which might mean Fine Track might indeed not be 9mm exactly.

[David]

It wouldn't surprise me because Japanese manufacturers have their own little world.  But if it was that different from Kato Unitrack you wouldn't be able to run N gauge trains on either Finetrack or Unitrack like we all do.

 

It's only different by about 0.3m, enough to make it out of gauge, but not enough to prevent most trains from running (but may prevent some trains from running well). Most Bachmann trains will run out of the box, despite out of gauge wheels being the norm for them (regauging those wheels can improve performance a lot by making the pickup less picky). There does need to be some breathing room between the flange and the rail, otherwise curves would be impossible, it's just that as you vary that space too much you get jerky or non-responsive trains (had a Model Power pair where one was out of gauge to the point that it couldn't run on Atlas sectional track, and had great difficulty even on bullet proof Unitrack).

 

I only have 2 Tomix trains (a loco and a brake car). Always disliked how the wheels on the brake car sat on the track, now I'll need to check both of them to see if Tomix is actually gauging them slightly smaller then normal to match it's own track.

[David]

I checked both a Tomix Yo 8000, and the new Tomix ED75-1000. The 8000's wheels where out of gauge to the same amount as the Finetrack. The ED75's wheels where also on the narrow side, and technically are out of gauge (they where too narrow to click into the gauge as they should) though not as much as the Finetrack or the brake car. Checking a few Kato locomotives and cars showed them to be in gauge as expected. I don't have any other Tomix cars to check, so I can't draw any specific conclusions - it could be that Tomix does use it's own special 8.7mm gauge for everything, or the rolling stock I have may just have poor quality control for the wheel gauge (not unusual for North American manufacturers, especially Bachmann and Model Powerin my experience).

[CaptOblivious]

David,

 

This is really fascinating. Could you share how to measure whether a wheelset is in gauge? I have a set of digital calipers and several Tomix, Kato, and Micro Ace sets and I would like to contribute to your dataset, but I'm not sure what precisely to measure, or what counts as in- and out-of-gauge.

[inobu]

The irony is, the same situation exist in the real world. It all depends on the usage of the train. A narrow gauge track allows for tighter turns which are better suited for railways that have space constraints.

 

Tomix runs different radii which would naturally alter the spec in their track gauge. Wider radii broader gauge. Their market is mostly JDM which have space constraints.

 

Kato supports a broader range market (U.S.) and needs to use a larger gauge track. Envision a SD90MAC on tram layout, hence unitrack's wider gauge to support their (Kato) markets.

 

Inobu

[KenS]

Kato supports a broader range market (U.S.) and needs to use a larger gauge track. Envision a SD90MAC on tram layout, hence unitrack's wider gauge to support their (Kato) markets.

 

I have to take exception to this.  Yes, narrower gauge track does allow for tighter turning radii in the real world, but that's a difference of a foot or more (e.g., Japanese 3' 6" or western U.S. 3' or even logging/industrial 2' gauge, versus 4' 8.5" Standard Gauge). That's a difference of 25% or more. The difference between 8.5 and 9mm (6%) isn't likely to be significant.

 

And I believe the real issue there is about wheel spacing (trucks on narrow gauge trains have the wheels closer together, so the can negotiate a tighter curve before the back wheel or front wheel is forced into the rail side by the rigid truck).

 

What you may be thinking about is how track gauge broadens (not narrows) in curves, to provide more room for wheel flanges and  reduce wear. That's a difference of about 1% in the real world (I found an article for a 5' (Russian Gauge) railroad where the broadening was from 1520mm to 1530mm in tight curves), but 6% might be necessary for very sharp curves.

 

If the Tomix wheels, but not the track, were built to a narrower gauge, then this could possibly be an explanation (I'd still be doubtfull), but if both are built to the same narrower gauge, I'd put it down to Tomix just doing it "their way".

 

That could affect a North American model on Kato track versus finetrack, as the trucks on an SD90 are much longer than those of a typical Japanese passenger train.  But even there, turning radius is often more about how sharply the truck can turn before hitting the frame or coupler mount, rather than flanges binding against the rail. I've only heard of flange binding being an issue with steam locomotive models, which have very long wheelbase frames for the driving wheels.

[bill937ca]

We should remember that Japanese train makers deal with two different track gauges and two scales with a single track product line and that their market focus is almost entirely Japan focused.  Even Kato's product line is overwhelmingly JR and Japan focused.

 

Here's three gauge/scale variations (including a what if-- if 1435 stock was produced at 150 instead of 160.)

 

1435 / 160 = 8.96875

1435 / 150 = 9.56667

1067 / 150 = 7.11333

 

I suspect Japanese modelers that want fine scale or near fine scale models are not buying from the mass market manufacturers like Kato, Tomix, Micro Ace, Greenmax but are buying brass or some other customized models.

[KenS]

This is really fascinating. Could you share how to measure whether a wheelset is in gauge? I have a set of digital calipers and several Tomix, Kato, and Micro Ace sets and I would like to contribute to your dataset, but I'm not sure what precisely to measure, or what counts as in- and out-of-gauge.

 

Well, I'm not David, but what you want are NMRA standards S-4.2 (wheels) (PDF) and S-3.2 (Scale Trackwork). There are a number of critical tolerances on wheels, as just measuring back-to-back separation doesn't tell the whole story, without knowing flange and tread width. For track, N is supposed to be 8.97 - 9.32 mm between the rails on straight track, with the wider spacing the maximum on a curve.  The NMRA recommends (RP-11) that streetcar track have a minimum N-scale radius of 70mm, and Interurbans of 127mm.

 

Of course, nothing says a Japanese manufacturer needs to conform to the NMRA standards.  They're effectively a recommendation for how to ensure trains and track built by different manufacturers will work together.

[inobu]

"I have to take exception to this.  Yes, narrower gauge track does allow for tighter turning radii in the real world, but that's a difference of a foot or more (e.g., Japanese 3' 6" or western U.S. 3' or even logging/industrial 2' gauge, versus 4' 8.5" Standard Gauge). That's a difference of 25% or more. The difference between 8.5 and 9mm (6%) isn't likely to be significant."

 

It is all geometry and is dependent on one another and suggesting that a foot is not significant? In N scale .5 mm equates to 11.2 inches almost a foot of deviation. That is a lot of deviation in the real world and would have the same effects in N-scale.  History states that the original standard was 4.8 and was adjusted to 4.85. That half a inch made the difference they needed.

 

I don't have derailing issues often because I only run Kato. When you start mixing and matching you start to open your layout to these kinds of issues.

 

The bottom line is any kind of deviation at any level has a cause and effect.

 

 

Inobu  

 

 

[inobu]

David,

I think marketing and manufacturing plays it role in how and what companies do. The patents for fine track and unitrack came out a few years apart. I have a feeling that the gauge difference started then (only speculation) based on the patents and the separation of the two markets.

 

Knowing this I decided to go with Kato only. By doing that I eliminated a lot of compatibility questions. It limits choices but the choices seems to be timed based anyway (meaning you have to wait for the releases to get what you want).

 

In any case your findings substantiates the need for others to ponder which track they are going to use before they start. 

 

Inobu