KATO Wye turnout..Problem

[railsquid]

Actually, my understanding from posts on other forums by Charlie Vlk (a U.S. model rail consultant who once worked at Kato USA) is that the so-called #4 turnout is the earlier and higher quality offering from Kato. The #6 came later, and the construction of the points/frog and the internal circuitry were "cost engineered" to a lower price point, to be attractive to U.S. modelers. If you compare a #4 and a #6 side-by-side, top and bottom, you will see the differences, such as the 2 moving points on the #6 being a single stamping.

 

Interesting, I wondered why they're similar-but-different. The other major discrepancy is that the #4 control wires are detachable whereas the #6 ones aren't.

 

 

I use #4's almost exclusively and have little problem with them, but I generally take a modeler's file and slightly feather the end of the moving points on the flange-side, as well as the top and flange-side of the end of the rails on all track sections. You can feel a slight lip on the railheads at the ends of the sections, from the way the rail pieces are "chopped" to length during the manufacturing process. I also don't glue down ballast on the Unitrack, which I believe can increase the likelihood of contact and point-throwing issues. It's also possible that the rail tops on two joined track sections are not level -- it is possible to have some vertical "slop" in the Unijoiner. Feel across the joints on the top of the rails with your finger, and experiment with gently trying to raise one section compared to the other one, or pushing the Unijoiner all the way down. By watching carefully, I have observed that the train wheels sometimes bump around and get unstable at the rail joint just ahead of the moving points, and their motion can remain jostled as they hit the point tips just a few cm away, and then they derail. You want to smooth the whole path of the wheels.

 

 

I've just discovered the ultimate track smoothness testing unit - the Kato Glacier Express locomotive, which has very small-diameter driving wheels (and some very low-slung body parts) - small differences in track height across unijoiners will make it come to a sudden halt, or derail it all together.

[Welshbloke]

B Train Shorty chassis are pretty good at finding all the wonky track joints too! I think it's because they use an inside bearing design with a fair bit of slop (on the trailer bogies anyway, the motorised ones are a bit tighter), rather than the pinpoint bearings on the ends of the axle as used by most other brands.

 

I have also noticed that you sometimes need to push the rail joiners down into the unijoiner, as they're prone to riding up at one end with the effects detailed above.

 

I've now filed a slight taper in the point rail tips on my #4s, but not yet had a chance to see if it completely solves the problem. I did notice that the point rails are prone to sitting higher than the stock rail, so the taper should help there as the wheels will be guided upwards (rather than hitting a square end head-on) and then press the rail down under their own weight.

[cteno4]

Tuning video