LGB points (turnouts) causing derailing issue.

Lez2000

Lez2000

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Hello all, I have a problem with a set of LGB 18150 points (radius 5, left hand manual point) in that any loco attempting to cross it is derailed. I've tried various weight locos and they all come to grief.
I've removed the offending points from the layout to have a closer look and found that the wheel flanges are 'bottoming out' when crossing the frog. The problem is worse when travelling from left
LGB points 1.jpg
to right. The biggest culprit is the mainline and to a lesser extent the turning. Before I strip it down does anyone have a cure or suggestion for this? The points are only a week or so old and purchased new. I really didn't expect this from LGB.
 
Firstly have you checked it is level?

Those contact strips on the frog do look high, but difficult to tell from the angle of your photo.

My largest radius is R3, so I'm not familiar with these larger points....
 
The other thing is that the point of the plastic frog can rise a little, this can cause serious pain. On the Ruschbahn where they were used extensively the solution was to put in a 10BA nut and bolt some 5 or so mm from the pointy bit. Have a look to see if they are rising some before you do this though once outside in the sun it is a likely problem for the future.
 
Gizzy said:
Firstly have you checked it is level?

Those contact strips on the frog do look high, but difficult to tell from the angle of your photo.

My largest radius is R3, so I'm not familiar with these larger points....
Click to expand...
Yes, it's currently sitting on the dining room table so it is level. I can also see daylight where the wheel is lifted as it passes over the frog.
 
dunnyrail said:
The other thing is that the point of the plastic frog can rise a little, this can cause serious pain. On the Ruschbahn where they were used extensively the solution was to put in a 10BA nut and bolt some 5 or so mm from the pointy bit. Have a look to see if they are rising some before you do this though once outside in the sun it is a likely problem for the future.
Click to expand...
Okay, thank you.
 
Flanges are supposed to bottom out a little through the frog, so that metal loco wheels can pick up from the metal strips at the bottom of the flangeway.

Check the plastic V is properly screwed down (2 screws underneath)? I replaced the plastic V on mine with metal rail and disconnected the bridging wiring, turning the point into a live frog design requiring a polarity changeover switch for the frog. It improved slow running for short wheelbase skateless locos.


6_brass_frog_2.jpg
 
Paul M said:
The moulding in the middle, the actual X bit looks dodgy. Is that where the wheels are scraping ?
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The flanges are hitting the contact strips that are set into the ‘x‘ although thinking about it, maybe that’s how it should work to maintain electrical contact through the frog.
 
ntpntpntp said:
Flanges are supposed to bottom out a little through the frog, so that metal loco wheels can pick up from the metal strips at the bottom of the flangeway.

Check the plastic V is properly screwed down (2 screws underneath)? I replaced the plastic V on mine with metal rail and disconnected the bridging wiring, turning the point into a live frog design requiring a polarity changeover switch for the frog. It improved slow running for short wheelbase skateless locos.


View attachment 264993
Click to expand...
Yes, I suddenly realised (while eating dinner) that the flanges should make some contact through the frog. I’ve checked the screws as suggested, nothing untoward there. Thank you.
 
You might try non-permanent shims on the guard rails. I have had to shim some units as much as 35 thousandths, most about 10 to 15. LGB points (switches) seem to have an excessive side play at the frog, allowing the wheel flanges to wander where they shouldn't.
---Hutch
1587585067020.png
 
Lez2000 said:
That thought had occurred to me but I also thought “how difficult would it be to disassemble it and have a look?”
Click to expand...

Well, if you do that then go back to the seller the answer you get will be along the lines, "You've tampered with it and that must have caused it not to work".
 
I agree with Gizzy, take a close look at the contact strips in the frog. The LGB metal wheel flanges are supposed to ride on the strips (so short wheelbase locos get power through the turnout) but if they were improperly installed they could be lifting the wheels too much. The wheels should just barely be raised going through the frog based on checking a LGB wagon with stock metal wheelsets on a new R5 switch I've got. I can only feel a very subtle "bump" as I roll the wagon through the frog. So check the frog molding itself too. It should smoothly raise the wheel flange. The flange shouldn't bang into it. There could possibly be some mold flash underneath the frog causing it to sit too high. If they look OK, try guard rail shims as suggested by Hutch.
 
The LGB switch design is "flange bearing", the flange is SUPPOSED to ride on the metal strips. There are TWO things going on here:

1. By riding on the flange, electrical power pickup to the wheel is maintained through the frog, so you can have a plastic frog, and still short wheelbase locos will run.

I think this has been figured out, but it is not intended to be "some contact" or "ride a little" on those strips. This is because of reason number 2:

2. By riding on the flange, you can actually lift the tread somewhat off the "rail" even the plastic part. The idea is that given the much sloppier tolerances of the toy trains "idea", the throat of the frog is larger, more open. The net result is that without being supported by the flange, the more open throat of the frog would allow the wheels to "drop into" the frog.

There are prototype examples of "flange bearing frogs"...

So, if you are derailing AND the wheels are riding on the flanges through the frog AND the metal inserts have not become dislodged, everything should be ok.

If you have derailments then, you need to check wheel gauge, or at least back to back on your rolling stock. Another thing that can happen is if the flangeway widths on the stock rails (the outer 2 rails) are too wide, that needs to be controlled... often a shim can help as show in Hutch's post.

So my #1 recommendation is check the back to back gauge your cars (but if all derail the problem is most likely elsewhere).
 
Finally some simple and good advice, from Greg....
Over the years, both Greg and I have seen rolling stock, "Brandy New/Out of The Box" that the wheel sets were out of gauge, to say nothing of rails being out of gauge. Most seem to fail to take this into account, and look everywhere else for the problems. This goes for products from virtually all manufacturers.
One thing every model railroader should have as a standard tool, is a track, and wheel gauge, and not a self made one....and use it on every wheelset, before the rolling stock is put into service.
Greg is also very correct in pointing out, that for wheels, the "Back-to-back" wheel gauge is the one you want.
One thing Aristocraft seemed to get right, was their simple wheel and track gauge...it was supposedly to NMRA standards. Too bad if using it on their equipment, it most often showed their wheels to be out of gauge, and their track was all over the place...!!!
Of course we run into the "What do we need STANDARDS for" group...….and all the common sense in the world will never convince them of the need for "Wheel and Track" standards...go figure....!!!
 
As Greg said check the back to back measurement of the wheels. It needs to be correct for the gaurd rails to guide the wheels through the frog properly.
Also, it might help if you specify some of the locomotives you have derailing.
 
Noting what has been said about the flange riding the metal to make contact, that was indeed part of the design as being of a larger radius the frog is longer and thus more of a challenge for smaller locomotives. Problem is outside that metal gets very tarnished and before each operating session on the Ruschbahn someone had to sand clean that metal with fine emery. No other option would be feasible, without that clean Corpets of which there were two running would not navigate the points at a sensible modest pace.
 
First of all a big thank you to all who've responded to my question. When I first posted it I must admit I wasn't really au fait with the workings of the points and saw the flange riding up as a design fault! I only started with G scale late last year and I'm still close to the bottom of the learning curve.

I've taken your suggestions (all of them) on board and will persevere. I will get there in the end.
Thanks again.
Les
 
One question that has not been asked. What make of wheel are you running over the frog?
 
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