# cars jump up while crossing frog



## graywolf06 (Aug 14, 2019)

I have a layout using Micro Engineering #6 switches. I notice that the cars jump up or rise up as they cross the frog. I appears that the metal of the frog is slightly higher than the tracks. How do people fix this? Is it possible to file the metal frog grooves lower to fix this or is there something else that is done?


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## wvgca (Jan 21, 2013)

depends on what is making the wheels jump, if it's the frog itself that a little too high, judicous application of a flat file would help ... if it's the grooves [doubtful] then either the wheels have a old style large flange, or the the grooves simply aren't deep enough [again, very doubtful]


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## graywolf06 (Aug 14, 2019)

I took your advice and measured the wheels of two different cars. One car has no preceived jumpup when I hold my finger on it as it crosses the frog. The other does. Both wheels on the cars measure exactly the same---.430" across the flanges and .380" on the tread. This gives a flange height of .025" is this considered normal dimensions?


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## mesenteria (Oct 29, 2015)

Good job dealing with this methodically. Next, use your NMRA scale gauge and determine if the picked wheels are in gauge. Chances are excellent that they are not, and if you'll have any trouble with mis-gauged wheel sets, it will be at the points and through the guards, or with the frog point at turnouts.


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## wvgca (Jan 21, 2013)

a flange height of 0.025 is considered normal for code 110 wheels .. if both wheelsets read the same, it might be the spacing of the wheels themselves ? you can measure this easily with a NMRA gauge, or calipers ..


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## graywolf06 (Aug 14, 2019)

Ok so I swapped the wheels and the problem shifted to the other car. Checked with the NMRA gage and see the problem wheels are slightly tight --too close together. Tried to pull them apart with my hands --no luck. How do you do it or do you buy new wheels. Thanks, Paul


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## D&J Railroad (Oct 4, 2013)

Are the wheels solid one piece with the axle? They should be in gauge. If they are plastic wheels and metal axle ya gotta twist them harder.


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## graywolf06 (Aug 14, 2019)

The wheels are metal with metal axles so there has to be a plastic bushing otherwise you would have a constant electrical short. Trying to devise a way to spread them maybe using a bench vise with metal plates attached to the jaws and then backing the vise open??? Just a thought --is it really worth it or just buy new wheels??


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## Dennis461 (Jan 5, 2018)

*be careful*

Be careful, it is pretty easy to bend an axle when wheels are tight.
If you 'invention' pulls crooked, you will be in worse shape.


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## graywolf06 (Aug 14, 2019)

Tried to spread them apart from outside dimension of .780" to .795" that fit the gage. No luck they wouldn't move. So I just bought some Kadee wheels on Amazon 12 for $11.59. Beats driving 22 miles to nearest hobby store and back. Thanks for all the replies. If this works well I will check all my other cars and change wheels as necessary.


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## Dennis461 (Jan 5, 2018)

graywolf06 said:


> Tried to spread them apart from outside dimension of .780" to .795" that fit the gage. No luck they wouldn't move. So I just bought some Kadee wheels on Amazon 12 for $11.59. ...


Good luck with your next adventure, learning about the multitude axle lengths


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## dalehenigman (Aug 21, 2014)

I have had some car wheels want to raise up going thru frogs, wheels checked out ok. Suspected that the wheels wanted to climb out of groove due to force of pushing/pulling long train (100 cars) thru turnouts. Helped the problem considerably by installing a new guide rail opposite the frog that was slightly taller and closer tolerance than the track rail.


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