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question about track building, in particular gauge 1/scaleone32 (1:32)

Quick reply >
I was building in prototypical p-32, however this is not going to fit the bill, sort of speak.
For the loco's i would like to have, with the room i have, it is simply not possible to go even near those dimensions.
Minimum radii is 3 meters, max i can do is 8 meter radii, but it will be 5 meter radii(oke will be six?)
There will be 3 loops in my garden layout, one loop is special for the bigger loco's!!!, those will go around the house and can only drive on the outsides of the garden.
Outer loop: AA20, big boy, challenger, red devil ect.
Inner loops all smaller but incl the flying Scotsman.
But the smaller ones will run also on the outer loop, this means turnouts crossings ect.
Some fiddle yards and for storage a trestle, i dont know anymore who it was that told me this, but thank you again! for a trestle.

I read on a other forum that between the stock rail and the guard rail is a gap of 3 to even 4!!mm(brand dependent)
In between the stock rail and the points also?
And the gaps by the frog between the wing rail and the point rail is also 3 to 4 mm gap.
I was like: WHAAAT?

What would you suggest to keep as gap?
Prototypical: not to do when it comes to drive a loco(out of my league and out of what i can afford or want).
G1mra: to small for what i want.
Nmra standards: i can get away with it for my bigger loco's, but there will be probably trouble ahead.
Lgb or similar standards.
Or grandfathers "all around big gap" standards?
Combine nmra with lgb/similair gaps?

What would you suggest for my scale 1:32, according for the gap?
And any suggestions about the back to back flange would be welcome aswel.
I have been experimenting with back to back 42mm and with a flange thickness of 1 mm, this works perfect with one boogie on a prototypical scale turnout(1:8-1:10), but now a 5 or a 6 wheeler non articulated frame loco.... let alone the AA20 a 7 wheeler?

As you already tasted, i overthink to much and regarding this topic/subject i am really swimming in the dark for the measurements, what to do???
For technical execution....oh man just wait, start to drool now and lick your fingers.

Any advice is and will be very appreciated.

With best regards Igor.
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Martin Wynne

West of the Severn UK
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@Justme Igor

Hi Igor,

I have never modelled in Gauge 1 or know much about it, so it's a bit daft for me to jump in and suggest standards dimensions. :)

However if I was modelling in Gauge 1 I wouldn't want to use any of the long-standing published dimensions.

Here are the G1MRA standards, flawed by making no allowance for blunt nose or any face chamfer on the wheels:


And here are the NMRA standards, with their ludicrous triple-dimensioning and a "target" track gauge of 45.01mm !



Here is what I would do. Probably.

The starting point is always the Wheel Width. How wide are your thinnest wheels?

For a garden railway the optimum wheel width on 45mm tracks would be around 7mm on typical existing tracks with 3mm flangeways.

However, both G1MRA and NMRA are specifying less than that, 6mm wheels for G1MRA and around 6.5mm for NMRA.

Assuming some of your models have 6.0mm wheels (and this will work equally well for running wider wheels), do this:

1. subtract an allowance for the blunt nose width. At 10mm/ft that should scale at 0.52mm for UK flat-bottom track and 0.42mm for most USA track. Let's split the difference and call it 0.45mm:

6 - 0.45 = 5.55 mm.

2. subtract an allowance for the face chamfer on the wheels. That might be about 0.3mm:

5.55 - 0.3 = 5.25 mm.

3. subtract an allowance for the top corner radius on the rail head. That could vary a lot for different rails, but let's call it 0.25mm effective support:

5.25 - 0.25 = 5.0 mm.

4. divide by 2:

5.0 / 2 = 2.5 mm crossing flangeway gap max.

This is the maximum crossing flangeway gap to ensure full support of the wheel through crossings (frogs), to provide the smoothest running. Any wider than this and you will get some bumpiness and clatter when running through crossings with 6.0mm wheels. Some modellers may prefer that of course.

To use wider crossing flangeways smoothly you would need wider wheels. If you repeat the above with 7mm wheels you get 3mm flangeways, for example.

5. Subtracting 2.5 mm flangeway gap max from the track gauge min, you get:

45 - 2.5 = 42.5 mm. This is the check gauge minimum on 45mm track. Write this down and don't ever forget it. :) It is the most critical dimension in all subsequent track building.

6. Subtract 2.5mm from the check gauge to get the nominal check span:

42.5 - 2.5 = 40.0 mm

7. Add say 0.3mm running clearance and an allowance for the crossing flangeway being less than max:

40.0 + 0.3 = 40.3 mm

This is the minimum back-to-back for the wheels. It seems some Gauge 1 models may have 40mm back-to-back. (For these consider using 44.5mm track gauge and 42.0mm check gauge instead.)

8. Assuming 1.25mm flange width, subtract it from the check gauge:

42.5 - 1.25 = 41.25 mm

This is the maximum back-to-back for the wheels. For other flange widths, adjust accordingly. i.e. If you are using 1.0mm flanges (which seem a bit thin to me), the maximum back-to-back would be 41.5mm.

9. Summarising the above, my suggestion would be:


track gauge: 45 mm min

check gauge: 42.5 mm min

crossing flangeway: 2.5 mm max


overall width: 6.0 mm min

flange thickness: 1.5 mm max

back-to-flange: 42.5 mm max


40.3 mm min​

41.25 mm max for 1.25 mm flanges​

For getting around sharp curves, the answer is simple -- widen the gauge until models will run around it. If you fit a continuous check rail on such curves, widen the check flangeway gap by the same amount. So on 46 mm gauge the check rail flangeway would be 3.5 mm.

Just to repeat, I have never modelled in Gauge 1, so I'm utterly unqualified to make the above suggestions. But it's what I would do if I intended to model in Gauge 1 in the garden.

Unless I change my mind over breakfast. :)


message ref: 3524

Martin Wynne

West of the Severn UK
Enjoy using Templot?

Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add
helpful replies.
p.s. Igor,

The above standards are not in Templot, so I will add them with the name 1-MF:


Will be in 233c shortly.

message ref: 3525