Wheel Dimensions Help

B

BPACH

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I am interested in building my own truck sets and am running into problems. I can not find a good diagram of the wheels with measurements for G scale. Every other scale, but not G. I need something with diameter, flange height, distance between rails, etc. Can some one point me please.
 
Gizzy

Gizzy

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Hullo Brian and welcome to the forum.

There are so many different scales and manufacturer's specifications for wheel-sets that make this a tricky one to answer.

I'm running on code 332 rail with LGB, Piko and Bachmann/Lilliput wheels. My scale is 1:22.5 European NG with some 1:29 Piko SG stock.

I assume you model US prototype, so your requirements may be different....
 
Rhinochugger

Rhinochugger

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I am interested in building my own truck sets and am running into problems. I can not find a good diagram of the wheels with measurements for G scale. Every other scale, but not G. I need something with diameter, flange height, distance between rails, etc. Can some one point me please.
That's because 'G' is not actually a scale - we'll forego the long, and very boring explanations.

So, you need the wheel standards for Gauge 1 - that'll do the trick :nod::nod:
 
ntpntpntp

ntpntpntp

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So, you need the wheel standards for Gauge 1 - that'll do the trick :nod::nod:

The standards typically used for Gauge 1 are finer than those used for G, which is why folk can have problems running Gauge 1 stock on LGB trackwork (wheels dropping into frogs for example), or problems running G stock on gauge 1 track (flanges running on the chairs).

B BPACH Why not simply buy an example piece of G rolling stock from LGB, Bachmann, USAT and take some measurements?
 
Greg Elmassian

Greg Elmassian

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Since the poster is in the USA, I'd like to correct Nick's remark (or you can read my web site).

The NMRA has several standards that affect "G", finescale, standard, and "deep flanges" (a way to include LGB and others that make to toy train standards).

Likewise G1MRA has "standard" and "fine" standards.

The point I am making is you cannot just say G1MRA or NMRA, but you need to adopt one of their standards. I make recommendations and review this on this page:

 
Rhinochugger

Rhinochugger

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27 Oct 2009
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North West Norfolk
The standards typically used for Gauge 1 are finer than those used for G, which is why folk can have problems running Gauge 1 stock on LGB trackwork (wheels dropping into frogs for example), or problems running G stock on gauge 1 track (flanges running on the chairs).

B BPACH Why not simply buy an example piece of G rolling stock from LGB, Bachmann, USAT and take some measurements?

It's only the LGB flanges that are out of kilter - the rest of the wheel standards are fine, and the point frog drop can be overcome - even that problem isn't universal, particularly with bogie rolling stock.

LGB uses deep flanges because of the use of R1 :rolleyes::rolleyes: without those extra deep flanges much of the rolling stock would de-rail.

Greg Elmassian is the expert on dealing with point frogs - I've messed about with my two Aristo #6 turnouts to prevent stock wobbling a bit, but the Aristo 10fts and the USAT #6 are reasonably OK with both bogie stock and 4w stock.

But, back to the point, the standards used (with the exception of the deep frogs) are G1 :nod::nod:

I have some G1 wheelsets, Accucraft Fn3, Bachmann Spectrum, and a few other odds and ends, and I don't have any running issues that are caused by the wheels - careful caveat ;);)
 
Greg Elmassian

Greg Elmassian

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Rhino, I need to disagree with your blanket statement... there are a lot of differences between the standards other than just flange depth.

In the NMRA spec, it's pretty clear when you look at the tolerances for the measurements, while there is a target value, the "toy train" standards have such broad tolerances there might as well be no standard (yes that is over the top).

Interestingly enough, when the NMRA overhauled the "G" standards, they pretty much copied G1MRA for ONE of the NMRA standards, but actually mucked that up a bit. (the "standard" standard, not the finescale or the toy train one)

I follow G1MRA pretty much myself, but keep my flange depth to 2mm or sometimes a tad more. Also the flange thickness not too thin.

On the LGB, they are designed to be a flange-bearing frog, i.e. the flange edge is supported in the bottom of the flangeway in the frog, not by the rail tops themselves.

This is a very interesting way of doing things, rare in the prototype, and if you run all your rolling stock with identical flanges, it can work well, all these dimensions interlock and interplay in a complex way.

This means if you want really good running, you need to follow a standard for the wheels and track and switches/points/turnouts. I define really good is running a mainline train of 40 cars up and down slopes with many switches and leaving it unattended for hours.

I won't go into the explanation here, but there is a very tight relationship between back to back tolerances, gauge, and the frog geometry, you cannot radically change one without changing the others. I learned this when I thought all I had to do was set the back to back gauge at 1.575"...

My site actually explains this... it was a real revelation when I started and had a mix of equipment and tried to make things better. One of my best friends was a track inspector for many years for the real railroads, what an education.

Greg
 
Rhinochugger

Rhinochugger

Retired Oik
27 Oct 2009
28,501
3,437
North West Norfolk
Rhino, I need to disagree with your blanket statement... there are a lot of differences between the standards other than just flange depth.

In the NMRA spec, it's pretty clear when you look at the tolerances for the measurements, while there is a target value, the "toy train" standards have such broad tolerances there might as well be no standard (yes that is over the top).

Interestingly enough, when the NMRA overhauled the "G" standards, they pretty much copied G1MRA for ONE of the NMRA standards, but actually mucked that up a bit. (the "standard" standard, not the finescale or the toy train one)

I follow G1MRA pretty much myself, but keep my flange depth to 2mm or sometimes a tad more. Also the flange thickness not too thin.

On the LGB, they are designed to be a flange-bearing frog, i.e. the flange edge is supported in the bottom of the flangeway in the frog, not by the rail tops themselves.

This is a very interesting way of doing things, rare in the prototype, and if you run all your rolling stock with identical flanges, it can work well, all these dimensions interlock and interplay in a complex way.

This means if you want really good running, you need to follow a standard for the wheels and track and switches/points/turnouts. I define really good is running a mainline train of 40 cars up and down slopes with many switches and leaving it unattended for hours.

I won't go into the explanation here, but there is a very tight relationship between back to back tolerances, gauge, and the frog geometry, you cannot radically change one without changing the others. I learned this when I thought all I had to do was set the back to back gauge at 1.575"...

My site actually explains this... it was a real revelation when I started and had a mix of equipment and tried to make things better. One of my best friends was a track inspector for many years for the real railroads, what an education.

Greg
OK, yes, I get where you're coming from and I'm also still comfortable with my last line above.

However, that doesn't mean that I won't find a wheelset that'll give me trouble.

Equally, going back to BPACH's original question - is NMRA the best for him, being resident in the USA?
 
Greg Elmassian

Greg Elmassian

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I would say that the NMRA "standard" standard is best, but to stay right at the target specs, and not use the wider tolerances specified.

this makes you almost exactly G1MRA except for slightly deeper flanges and some other nuances.

Most of this recommendation is due to that the American prototypes tend to have more axles, and thus the loco, whether steam or diesel, more sensitive to the track warp and vertical transitions.

An example is the Aristo 3 axle diesel truck which is basically unsprung. The slightly deeper flanges wiill help avoid derailments better.

I've spent many hours with my eyes at track level really seeing what is going on, to see things that can lead up to derailments.

Greg