GP38 Stopping on gg switches

It could be a roller "spacing" problem. Use your volt meter and make sure there is power on the center rail between the 2 switch frogs.

In all probability, it's a roller spacing issue. Make sure the center rail between the turnouts is live AND the outside rails on both sides are tied to common. If this is an Atlas turnout, don't rely on the internal wiring of the hot leads.

 

If that's already been done, you may need to temporarily use the closure rails as "hot" extensions by connecting them to relays such that when the turnout is open, the straight closure rail is energized. If you're using Tortoise machines, you can use the extra contacts. Otherwise, you'll need to use a relay.

Is this a Williams GP38 or a Lionel O gauge GP38-2?

 

Andrew

Sorry bit of misinformation. It's a MTH GP9 not the GP38. It is worst going over the switch in one direction than the other. Losses power running through slowly and sparking. This engine did this on my previous layout through switches as well as my memory serves me. This is gg #7 switches which form crossover. No other engines have problem. Like this engine and hate to not run it. Going to try it on another loop see if a problem there. I have checked power/ground through switches and seems fine.

Does the engine have two single rollers?  If so, you can solve spacing problems by changing out one of the single rollers with a double roller ordered from MTH parts.

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Dennis

Are all the outer rails grounded? Have an MTH unit and a Lionel that will stop on a crossing where all the rails are not yet grounded. (They do go thru in the opposite direction!!) With two rubber tires there is only one axle of two wheels to complete the circuit. They both run thru it flawless if you jump the "open" outer rail to common.

       
       




Wouldn't this be the case with all engines? Also would this cause sparking?

       
       

Yes single rollers. Again though does that cause the sparking? Could it be the bolsters and wheels guageing itself?

You would think so. Have 2 Lionel FM's. One will run thru, the other no. If you turn them 180 degrees they both go thru.  Sparking is usually from not good constant contact. Where does it spark? Does it spark everywhere? All turnouts? Down the straights? Roller might need to be cleaned on the pin? Wheels clean?

       
       

Thanks for your help. Don't notice sparking except on this switch. I think it's a contact issue as I can get contact by holding engine and moving it a little.

The sparking can be a separate issue from the stopping. You should be able to see what is contacting what with slow operation and eyeballing it.  Generally it is a wheel flange contacting a hot rail.  A piece of tape at the contact point of the rail will fix it.

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Dennis

 

When it gets there and stops, try just touching a truck and gently push it towards the opposite rail. If the engine suddenly comes to life, Id lean towards losing it the ground (common rail) contact. You can also check all the rails with a meter, could be a solder joint failed underneath. Had that happen at a friends on a double crossover. Does the center roller spark or the wheels?

 

Dennis has a quick idea for shorts, have seen it used where steam engine drivers hang in too far and short the diverging center rail while passing thru on switches.

Thanks, guys for all your help. I will have to investigate this more.