Frog problem

[1arfarf3]

What is the cause of a car wheel dropping into an HO NS Atlas code 100 frog? Any certain versions i e Mark 3, 4, etc?  Recommended fixes? Only happens on some frogs.

[dstarr]

Use the NMRA gauge to check the guard rail clearance.  The guard rail is supposed to press against the back side of the wheel and keep the wheel flange pressed up against the stock rail.  If the guard rail is set too wide,  the wheel set slides over toward the frog and bangs on the nose of the frog, or other badnesses.  If the guard rail clearance is too big, a thing piece of styrene strip can be superglued to the guard rail to close it up. 

 

[gregc]

dstarr

Use the NMRA gauge to check the guard rail clearance

isn't it more likely that the wheels on a particular car are out of gauge and need to be corrected than the guard rail clearance on a commercial turnout is incorrect?

[BigDaddy]

Both are possibilities but again we get a bare minimum of info.  Is this one car wheel, a tiny short wheel based loco, wheels on all cars or wheels on only certain cars. 

Aren't Atlas frogs known for inadequate vertical clearance for the wheels at the frog?  Maybe the dropping the OP sees is really a bounce.

[IRONROOSTER]

In addition to the above, make sure the turnout is flat.

Good luck.

Paul

[dinwitty]

code 100 frogs are more designed for the deep flange standard fromn the older days of HO and european standards, go ahead and check the turnout and car for problems. so todays cars might bounce into the frogs, the flange is supposed to keep the truck up as its supposed to ride on the frog rail bottom, but its too deep.

[hornblower]

Also remember that Atlas Code 100 turnouts were designed for wheels with the NMRA standard .110" tread width.  Some newer rolling stock comes equipped with "Semi-scale" wheels with .088" tread width.  Guard and flange rails set for the standard .110" wheel tread width may be too wide for the .088" wheel tread width.

[Anonymous]

hornblower

 Guard and flange rails set for the standard .110" wheel tread width may be too wide for the .088" wheel tread width.

 

The inside dimension between the flanges on a code 88 wheel are identical to a code 110 wheel set.  You can use the same NMRA standards guage to check this dimension.  The only way that a guard rail could cause a problem is if it is out of position.  What is a flange rail?  Im going to assume you are talking about the wing rails of the turnout.  Code 88 wheels can drop between the wing rail and the nose of the frog.  Newer turnouts have frogs where the wheels actually ride on their flanges as they go through the frog to prevent this from happening.  

To the OP:

If you dont have an NMRA standards guage you should get one.  Also does this video look like the problem you are experiencing?  https://www.youtube.com/watch?v=FXJTDhGZeFE

Or do the wheels drop in?

This shows what should be happening:

https://www.youtube.com/watch?v=MbSmoUH1Cqk

 

 Also a good video:

https://www.youtube.com/watch?v=JBdWvMHEN8s