Wheel Flange Rub: bad gauge or a fact of life?

KylePearce

KylePearce

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I have a 2-axle LGB railbus I’ve been running fairly often. Recently on the switches of my layout, I noticed some sparkly brass dust in the wheel channels. This was alarming, as I don’t want to unduly wear out my track. Inspecting the rail profile it seems merely polished on the inner edge, not worn. I’m sure the flange is to blame for this, but what I’m not sure about is gauge. The Railbus has pivoting axles which can accommodate quite sharp turns. However on my layout I don’t see them pivoting much at all, as if they don’t need to. I know wheels too far apart will derail, but what about wheels to close together? Is this dust a natural part of running, or is a too-narrow axle causing the track to not guide the axle into a turn like it should?
 
The only experience I've had of this, is of the Stainz running on a shuttle track at my local model shop.

After around 20 years of shuttling back and forth, there was evidence of brass dust on the R1 curves.

The proprietor replaced all the track with new.

I have a length of worn 10600 track from the shop, used on the shuttle which he donated to me. It had worn down at the railhead, and it is now used as my DCC programming track....
 
KylePearce said:
Is this dust a natural part of running, or is a too-narrow axle causing the track to not guide the axle into a turn like it should?
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LGB R1 curves are extremely tight in terms of prototype practice so you will get some signs of wear if you run mental wheel sets through them. Unless you are running continuously, as in Gizzy's shop example, it is not something to be particularly concerned about.

For unpowered rolling stock there are a few third party solutions that can steer the axles somewhat into a curve, but again, unless you are running long wheelbase vehicles a lot they are generally not necessary. I have fitted all my long wheelbase LGB RhB Lb-k container wagons with wheel control as I like to shunt them and it does help in backing them through reverse curves in the yard, but it was a tedious job and I have not bothered doing it either any other cars (at least yet).
 
Well, you can check the back-to-back measurements of you wheel-sets.

Make sure the railbus pivot freely. - Is something binding, perhaps?

Is your track level? - Especially across the formation?
Points (turnout) and curves, are notorious for track riding-up and twisting.

But as stated, our curves are ridiculously tight, and brass is a relatively soft alloy, so you will get some wear.

PhilP.
 
Thank you all for the quick reply, and putting my mind at ease. I’ll definitely check the gauge to be sure, but I do believe this is another classic case of overthinking.
 
PhilP said:
Well, you can check the back-to-back measurements of you wheel-sets.

Make sure the railbus pivot freely. - Is something binding, perhaps?

Is your track level? - Especially across the formation?
Points (turnout) and curves, are notorious for track riding-up and twisting.

But as stated, our curves are ridiculously tight, and brass is a relatively soft alloy, so you will get some wear.

PhilP.
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Yep, and LGB flanges are excessively deep; designed that way to keep trains on those extremely tight R1 curves - a vicious circle if you'll excuse the pun.
 
Some narrow gauge railways had plunger-operated flange oilers on tight radius curves. Obviously not helpful in our scale, but it was/is a real-world problem, just scaled down a bit!
 
Northsider said:
Some narrow gauge railways had plunger-operated flange oilers on tight radius curves.
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There was an article on RTL TV about the trams in the city where they have perforated rails on the tight curves. As a tram approaches an electronic sensor is tripped which causes oil to be pumped up through the perforations while the tram passes. The rails are set in a channel to catch the spent oil. All rather smart.
 
KylePearce said:
I have a 2-axle LGB railbus I’ve been running fairly often. Recently on the switches of my layout, I noticed some sparkly brass dust in the wheel channels. This was alarming, as I don’t want to unduly wear out my track. Inspecting the rail profile it seems merely polished on the inner edge, not worn. I’m sure the flange is to blame for this, but what I’m not sure about is gauge. The Railbus has pivoting axles which can accommodate quite sharp turns. However on my layout I don’t see them pivoting much at all, as if they don’t need to. I know wheels too far apart will derail, but what about wheels to close together? Is this dust a natural part of running, or is a too-narrow axle causing the track to not guide the axle into a turn like it should?
Click to expand...
Just a thought on this are the flanges showing any signs of excessive wear?
 
It's basic metallurgy. If you rub a hard piece of steel against soft brass the brass will wear faster than the steel. The only way to overcome it is to design a flange lubricator for G scale.
 
dutchelm said:
It's basic metallurgy. If you rub a hard piece of steel against soft brass the brass will wear faster than the steel. The only way to overcome it is to design a flange lubricator for G scale.
Click to expand...
Basic engineering, a slip differential so both wheels on an axle turn at different rates, eliminating the rub ;)
 
Following up, I checked how the wheels sit on the rails and there is a lot of sideways slop, as if the axle is too short. To clarify, this issue is the flange dragging along at too steep an angle. If I manually “align” the axle before the turn, the noise basically goes away and there is visibly less friction. I did some experiments with a test axle and narrow-set wheels like to ride crooked on corners. Should shim them outwards on the model, or should there be a substantial amount of sideways movement on the rails? This isn’t a fixed axle model, to be clear. They can pivot. I understand the need for a gap on my non-articulating trams. I did some research and it seems LGB wagons are known for their axles not following curves, and there is a lever kit that synchronizes them. Trouble is, no room on mine. I need to solve it with wheel spacing, if possible.
 
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KylePearce said:
Following up, I checked how the wheels sit on the rails and there is a lot of sideways slop, as if the axle is too short. I did some experiments with a test axle and narrow-set wheels like to ride crooked on corners. Should shim them outwards on the model, or should there be a substantial amount of sideways movement on the rails? This isn’t a fixed axle model, to be clear. They can pivot. I understand the need for a gap on my non-articulating trams. I did some research and it seems LGB wagons are known for their axles not following curves, and there is a lever kit that synchronizes them. Trouble is, no room on mine. I need to solve it with wheel spacing, if possible.
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The back-to-back measurement should be 40.5 mm (back of flange to back of flange)

There is quite a lot of play. If you mess about with the back-to-back, you could end up having trouble when running through points (turnouts).
 
Rhinochugger said:
The back-to-back measurement should be 40.5 mm (back of flange to back of flange)

There is quite a lot of play. If you mess about with the back-to-back, you could end up having trouble when running through points (turnouts).
Click to expand...
Does the flange width vary enough to matter? Or is this for all wheels? I’ll have to play around more with the test axle before I do anything to the actual model.
 
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KylePearce said:
Following up, I checked how the wheels sit on the rails and there is a lot of sideways slop, as if the axle is too short. To clarify, this issue is the flange dragging along at too steep an angle. If I manually “align” the axle before the turn, the noise basically goes away and there is visibly less friction. I did some experiments with a test axle and narrow-set wheels like to ride crooked on corners. Should shim them outwards on the model, or should there be a substantial amount of sideways movement on the rails? This isn’t a fixed axle model, to be clear. They can pivot. I understand the need for a gap on my non-articulating trams. I did some research and it seems LGB wagons are known for their axles not following curves, and there is a lever kit that synchronizes them. Trouble is, no room on mine. I need to solve it with wheel spacing, if possible.
Click to expand...
Of course the out rail is longer than the inner rail, so as the inner wheel progresses, then the outer wheel gets left behind, and has to “skip” to catch up.
 
KylePearce said:
Does the flange width vary enough to matter? Or is this for all wheels? I’ll have to play around more with the test axle before I do anything to the actual model.
Click to expand...
No, flange width doesn't really have an impact unless you are using home made wheels with very wide flanges.

Back-to-back is the critical dimension because of the way that the check rails guide the wheels through points and crossovers - they hold the wheel in line where there is a gap in the opposite rail.

On 1:1 railways, the flanges do not keep the rails on the track (wheels stay on the track because of their conical profile) but the back of the flanges are guided by check rails through points, crossovers and very tight curves.
 
KylePearce said:
I’ve got 39.7 mm back-to-back.
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That's probably OK, and you may not be able to adjust it. G1MRA standards are 40-40.5 mm back-to-back. It would take a brave man to argue about 0.3 mm.

Most LGB wheelsets are not adjustable ............... I think - I haven't had a lot of experience with LGB products.

I don't think you need to be too concerned; as many people have said, I think the issue is most likely the by-product of the tight curves. More important is that your trains run through points and crossovers without de-railing - keep 'em running and we're all happy bunnies ;);)
 
KylePearce said:
Following up, I checked how the wheels sit on the rails and there is a lot of sideways slop, as if the axle is too short. To clarify, this issue is the flange dragging along at too steep an angle. If I manually “align” the axle before the turn, the noise basically goes away and there is visibly less friction. I did some experiments with a test axle and narrow-set wheels like to ride crooked on corners. Should shim them outwards on the model, or should there be a substantial amount of sideways movement on the rails? This isn’t a fixed axle model, to be clear. They can pivot. I understand the need for a gap on my non-articulating trams. I did some research and it seems LGB wagons are known for their axles not following curves, and there is a lever kit that synchronizes them. Trouble is, no room on mine. I need to solve it with wheel spacing, if possible.
Click to expand...
Yep, we're actually trying to do something in the model world that is way outside the concepts of the 1:1 world.

Pivoting single axles are a pretty hideous concept. They tend to work better on wagons being hauled because the coupler connects to the 'bogie' and helps to turn and straighten it at appropriate points.

For a motor coach or tram, you probably have two options:
  • Cobble up a linkeage like the proprietary one that you have seen - I'd guess it involves a diagonal link between outer edges of the two bogie trucks.
  • Use a shorter wheelbase chassis without the pivoting trucks.
The Piko railbus had pivoting trucks and, I believe, used guides on the back of the skates to help turn the bogies - that will need a bit of confirmation from someone who has one.
 
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