Minimum radius for 2 ft. gauge

Discuss park gauge trains and large scale miniature railways having track gauges from 8" to 24" gauge and designed at scales of 2" to the foot or greater - whether modeled for personal use, or purpose built for amusement park operation or private railroading.

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Springhill-RR
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Minimum radius for 2 ft. gauge

Post by Springhill-RR »

Using a set of driving wheels that are 20" in diameter and 34" center to center on the axles.
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Bill Shields
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Re: Minimum radius for 2 ft. gauge

Post by Bill Shields »

A bit more info needed before providing meaningful response:

How many driving axles?

How many leading or trailing axles?

Side play in driving axles?

Side travel or play on leading or trailing axles?

Any blind driving axles?
Too many things going on to bother listing them.
Glenn Brooks
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Re: Minimum radius for 2 ft. gauge

Post by Glenn Brooks »

Here is an informative and similar thread.

http://www.chaski.org/homemachinist/vie ... hp?t=94864

It’s a quick read as only 5 or 6 replies. The essence is, the trailing truck can disproportionately increase minimum turning radius.

Also, a quick rule of thumb mentioned is: wheelbase (W) times 20 = minimum turning radius (R)

So in your case - 34” x20 = 680”
Or, R= 56.7’.

A respectable minimum turning radius considering 20” drivers, which implies a fairly large locomotive- in the 4” (1/3 rd) scale class.

BTW, I recently acquired Ben Hammer’s complete pattern set for casting parts for his 4” scale 4-4-0 American. The drivers are 20” diameter spoked wheels. Could also be used for an Atlantic 4-4-2 in similar scale and gauge.
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Glenn
Moderator - Grand Scale Forum

Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....
Curtis_F
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Re: Minimum radius for 2 ft. gauge

Post by Curtis_F »

Some factors to take into account:
Min_Radius_Set_By.png
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Springhill-RR
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Re: Minimum radius for 2 ft. gauge

Post by Springhill-RR »

http://www.catskillarchive.com/rrextra/plate097.Html

This is the model we are working on. It is scaled for 2 ft. gauge.
K. Browers
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Re: Minimum radius for 2 ft. gauge

Post by K. Browers »

Hello Friends
A Forney type of locomotive will require a larger turning radius than even a short wheelbase 0-6-0 this is due to its greater distance from the front driver to the truck pivot . That distance will determine the minimum radius . You could make the same locomotive with a short 4 wheel tender and get close to the same appearance. If you really want a Forney type may I suggest looking into some of the Mason Locomotive works engines.. they were articulated and would go around sharper curves.. if I recall correctly I think porter advertised their 0-4-0 locomotives going around 25 foot radius curves.you have a nice project ahead of you happy building..
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Re: Minimum radius for 2 ft. gauge

Post by Curtis_F »

Springhill-RR wrote: Mon Aug 30, 2021 10:19 am http://www.catskillarchive.com/rrextra/plate097.Html

This is the model we are working on. It is scaled for 2 ft. gauge.
As K. Brouwers notes the limiting factor for the minium radius on a Forney is the swing of the Trailing Truck.

Mr. Jack Bodenmann found a solution to alleviate this problem by getting rid of the traditional swing bolster and instead using roller bearing ( https://www.mcmaster.com/track-rollers/ ) to make a bolster that would roll side-to-side in a channel. This allowed his 3-3/4" scale 7-1/2" gage 2-4-4T #9 to negotiate much tighter radii than it would have normally been able to.

Figure out how much travel you'll be able to get on your Trailing Truck and that will tell you the minimum radius of track.
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Springhill-RR
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Re: Minimum radius for 2 ft. gauge

Post by Springhill-RR »

I plan to make the tender separate.
James Powell
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Re: Minimum radius for 2 ft. gauge

Post by James Powell »

2" gauge minimum radius can be...very tight.
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apm
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Re: Minimum radius for 2 ft. gauge

Post by apm »

James, where is that locomotive, British looking machine with an American style box car in the background pretty odd I would say. If it weren't for the background it looks a lot like the little railroad at the London Steam museum at Kew Bridge.
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Bill Shields
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Re: Minimum radius for 2 ft. gauge

Post by Bill Shields »

Freight container is Evergreen Taiwan...which means nothing..they are everywhere

Statfold barn rwy in the UK.
Too many things going on to bother listing them.
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Erskine Tramway
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Re: Minimum radius for 2 ft. gauge

Post by Erskine Tramway »

My 1919ish Koppel '100% American Owned, General Catalog Number One' shows 30-foot radius on their 2-foot gauge portable track. They also had 12-foot radius switches.
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So, that would probably indicate what was 'standard' at the time. Admittedly, the equipment, cars and locomotives, was probably all 4-wheeled.

Mike
Former Locomotive Engineer and Designer, Sandley Light Railway Equipment Works, Inc. and Riverside & Great Northern Railway 1962-77
BN RR Locomotive Engineer 1977-2014, Retired
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