LGB U series and switches

I will try all suggestions later.
Could the frog issue be solved by sanding them down and/or removing the skates? Sorry for the basic question!
 
HGLR said:
I will try all suggestions later.
Could the frog issue be solved by sanding them down and/or removing the skates? Sorry for the basic question!
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Skates can be sorted by a little bending upwards, best removed for this task. Reversely it is not all locomotives that suffer the shorting!
 
Its not the skates, which I have tweaked upwards so no longer in contact, and the wheels test fine on the Kadee when moved side to side so the "bullets" are working. I am coming to a conclusion that it is the sprung pair of centre wheels which are causing the frog problem. I think these are the only ones in my inventory built with this feature and one of the two locos definitely unbalances when stuck on the frog of some but not all of the R3 points. The spot where it sticks is so close to the skates that they could be seen to carry the blame but I believe have been found not guilty!
 
Your problem is likely to be a combination of things.
Did you also test the trailing wheels for picking up current?
Have you tested the actual point rails for current on the offending points?
 
Paradise said:
Your problem is likely to be a combination of things.
Did you also test the trailing wheels for picking up current?
Have you tested the actual point rails for current on the offending points?
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Thanks. Yes to both but checking Also with the wiring diagram I don’t think the trailing wheels have any connectors to pick up current.
 
HGLR said:
Thanks. Yes to both but checking Also with the wiring diagram I don’t think the trailing wheels have any connectors to pick up current.
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Yes to both? Therefore the loco will run just from putting power to the trailing wheels. Is that what you mean?
The early 2073 green one and 2071D Zillertal do. You should be able to see the carbon brushes at the top of the wheels from underneath or see the wires from the rear of the locomotive if so.
 
Paradise said:
Yes to both? Therefore the loco will run just from putting power to the trailing wheels. Is that what you mean?
The early 2073 green one and 2071D Zillertal do. You should be able to see the carbon brushes at the top of the wheels from underneath or see the wires from the rear of the locomotive if so.
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On my two the trailing wheels have no power pickups.
 
HGLR said:
On my two the trailing wheels have no power pickups.
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OK. The driver wheelbase is shorter than the movable point rails. When driving slowly does the loco stop when the drivers are all sitting on the point rails or are they over the frog?
 
Paradise said:
OK. The driver wheelbase is shorter than the movable point rails. When driving slowly does the loco stop when the drivers are all sitting on the point rails or are they over the frog?
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Over the frog and usually it is one of the sprung centre wheels that are on the frog and creating the tilt which lifts one of the rear wheels from contact with the rail. If I touch a screwdriver between wheel and rail at that point the loco starts to move.
 
HGLR said:
Over the frog and usually it is one of the sprung centre wheels that are on the frog and creating the tilt which lifts one of the rear wheels from contact with the rail. If I touch a screwdriver between wheel and rail at that point the loco starts to move.
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OK, you did say that before. Your locos can only get electrical pick-up from the drivers and sliders.
The combination of a flange bearing frog, a stiff sprung centre driver and the rails adjacent to each side of the frog not being perfectly level is most likely the problem.
Check with a straight edge from the end of the R3 point track over the frog to where the points pivot. As mentioned before you may have a hill at the frog. If so, reset the entire R3 point track perfectly flat. Screw it to an over length board if need be so the adjacent track section joins are flat too.

Not having trailing wheel pick-ups creates the problem of needing track perfectly level for the drivers and sliders to do the task of picking up current.
The sliders should still drop to the rails but perhaps it stops when they and the centre driver are both over the plastic frog. The sliders are between the first and second driver.
Don't sand down the frog. They are engineered to work just as they are. Other issues may be created.

If the problem persists, you could add some rear pick-ups as on the earlier models like below. The pick-up itself looks like a separate part screwed in place. I'm not sure if LGB/Marklin has them as spare parts.

LGB_UClassRearPickups_5783.JPG
 
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HGLR said:
I have two of the LGB U series, 20721 fitted with a MTS decoder and 20705 which came with the Zillertal set which was already MTS. My problem is that the 20721 runs smoothly over switches even at lowish speeds. The 20705 has to be running fast or it will stop on the switches. Before opening anything up do any other uses have a similar problem/solution? Thanks.
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Back to the beginning, isn't this a question of why 2 similar locos run differently on the same switch?

maybe one decoder has more "stored charge" via caps on the decoder and the other decoder resets/stops, and in reality both locos are getting an interruption in power pickup?

And one decoder handles it well enough to keep going and the other doesn't? This certainly seems possible.

They are not using the same decoder. I run DCC and I have seen the "continuing without power" "range" or "distance" vary between decoders.


Greg
 
Greg Elmassian said:
Back to the beginning, isn't this a question of why 2 similar locos run differently on the same switch?

maybe one decoder has more "stored charge" via caps on the decoder and the other decoder resets/stops, and in reality both locos are getting an interruption in power pickup?

And one decoder handles it well enough to keep going and the other doesn't? This certainly seems possible.

They are not using the same decoder. I run DCC and I have seen the "continuing without power" "range" or "distance" vary between decoders.


Greg
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Good thought. Would fitting a Massoth power booster help with this, assuming there is room inside to fit one?
Meanwhile I will be checking the point alignment as suggested.
 
I have 7 of these little beauties of all ages and versions. They run through points better than any other of my locos but, I encountered issues with almost all of my LGB R3s. I have now changed all to Piko. I appreciate they can have their problems particularly the poorly made early ones but the issues are resolvable.
I suggest looking hard at the points as you seem to have covered potential issues with the loco itself.
 
Is it possible that the point moving rails don not always have power? I have added solder braid to some troublesome switch/points.
 
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