derailing at turnout points

[GLS]

I have used tortise switches in an under table application. The standard .027 wires were too short so I used .029 music wire. When trying to pass through the closed switch points the rolling stock doesn't pass between the point and the rail, but up and over thereby derailing. I have tried adding weight to the cars but it takes as much as 4 ounces to provide enough weight.

[gregc]

Originally Posted by GLS

I have used tortise switches in an under table application. The standard .027 wires were too short so I used .029 music wire. When trying to pass through the closed switch points the rolling stock doesn't pass between the point and the rail, but up and over thereby derailing. I have tried adding weight to the cars but it takes as much as 4 ounces to provide enough weight.

are the wheels on the truck too wide, or the rails too tight (based on an NMRA gauge)?

[GLS]

the wheels and track are both in compliance

[dave1905]

Originally Posted by GLS

When trying to pass through the closed switch points the rolling stock doesn't pass between the point and the rail, but up and over thereby derailing.

Are you running through a closed switch and expecting the wire to act like a spring switch? That won't work.

[Selector]

This has three possibilities in my experience: gauge too wide on the flanges or the points rail isn't sitting flush to the stock rail with its sharpened tip there as well...flush. Many commercial turnouts need the very tip of the point both sharpened quite a bit and tweaked to sit flat against the inner face of the stock rail.

A third possibility is that as the rolling stock enters the points end of the turnout, a slight shift of the turnout causes the throwbar to slide a bit and it moves the point away from its stock rail just enough to lift the flange. Try preventing the throwbar from moving by snagging it with a wire or hook and holding it fairly tight to the one side while your cars engage the points. If you don't get the unwanted behaviour, you now know what to do.

[Y3a]

Originally Posted by dave1905

Are you running through a closed switch and expecting the wire to act like a spring switch? That won't work.

TWO VOTES FOR THIS ANSWER!

Adding weight to cars wears the plastic truck frames out too. NMRA weights are too heavy and old school.

[Burlington Bob]

Originally Posted by dave1905;

Are you running through a closed switch and expecting the wire to act like a spring switch? That won't work.

By the original poster GLS;

When trying to pass through the closed switch points............

Three votes!

[Trussrod]

Say Gls,
Is the .029 music wire possibly sticking up too far so it hits the axels of cars passing over it?

As Crandel said you also need to check the points to ensure they are flush against the stock rail which should have a bit of a relieved section to allow the points to recess against it a bit. Also be sure the leading edge of the points have a slight champher to them and not a sharp of blunt end. It should be a smooth transition from the stock rail onto the point rail.

Hth

[Charles Smiley]

Creep the train very slowly through the switch and observe in minute detail what happens. Also try backing the train through the switch (so the loco isn't involved) and see what happens.

[John P]

Yet another way to lose is if the track isn't laid on a level base. If there's a twist--one rail going down or up--the truck can find itself with a wheel lifted off the rail, and once that happens, it's very easy for it to travel across the rail and come down on the wrong side. I found this out by watching the action as cars crossed a persistently derailing turnout.