7" gauge in the garden

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7¼" gauge in the garden

Workshop

 

On the workbench      On the drawing-board      Reference

On the workbench

POEM

 

Purchased from Murray Lane of Auckland in June 2008, POEM is a semi-freelanced 2-8-0 based upon a WWI trench loco.

CLICK HERE for more info on POEM.

My petrol hydraulic

 

Since my petrol hydraulic transmission arrived from the UK I have been pondering what style of loco to build. I decided that I would not start until POEM was back and running so that I didn't get distracted.

I always had a soft-spot for the MinitrainS H0n30 Plymouth. The more I think about it, the more I like the idea of building one in 7¼" gauge.

CLICK HERE for more information on my petrol hydraulic

 

Passenger carriages

 

John Bremner and I are currently building a new carriage that will sit on the drawbar of my trailer. Number 1 is too long and too heavy to carry about for the odd occasion when I'd need my own ride-car, so a short one is good enough for now.

Freight wagons

 

I have always had a soft spot for the classic V-tippers that were built in the thousands for industrial use all over the world. They are also very practical for construction purposes on a railway.

I have been working on-and-off on some CAD drawings to build some from profile-cut steel. 

On the workbench      On the drawing-board      Reference

On the drawing-board (or at least ideas in my head)

The big diesel

 

I have recently come into contact with an ex-automotive engineer who has offered some of his spare equipment for an experiment. He has a 5kW generator looking for a home and is keen to see if he can build the "guts" of a locomotive in exchange for website development for him.

Sounds like a good deal to me!

Long-term projects and ideas

  In November 2008 I picked up a complete set of drawings for an Orenstein & Koppel rack loco to the design by Ken Swan. Not sure if I want to undertake this as a "first build" so might look for something a bit simpler but it would make a fascinating model.

Plans are also available (I don't have them) for an adhesion-only 0-6-0 which uses a lot of the same parts.

I am trying to find out whether castings (or patterns for them) are still available.

There are apparently two Koppels in New Zealand. One is based around Havelock North (it has been seen there on several occasions - see the Havelock North photo gallery) but I do not know where the adhesion-only 0-6-0 is. I am trying to track it down.

 
  A friend in Sweden is researching a Decauville Type 6 and will produce drawings for one for 7¼" gauge.

This would be a project I would really enjoy.

(Prototype photo taken on the Bredgar & Wormshill Light Railway, UK)

On the workbench      On the drawing-board      Reference

Reference

 

It is worth noting that the 7" Gauge Society and the Model Engineering Association of New Zealand (MEANZ) approved track and wheel standards are not quite the same.

MEANZ approved standards

CLICK ON image to view / save full-size

7" Gauge Society (UK) approved standards

FLANGEWAYS

  On diagram above Standard Gauge Narrow Gauge
Fractional " Decimal " Metric Fractional " Decimal " Metric
Flangeway "A" 9/32

-0 +1/32

0.281

-0 +.031

7.15

-0 +0.79

9/32

-0 +1/32

0.281

-0 +0.031

7.15

-0 +0.79

Maximum gauge widening on curves   1/8 0.125 3.18 1/8 0.125 3.18
Track gauge "B" 7 1/4

-0 +1/64

7.25

-0 +0.015

184

-0 +0.38

7 1/4

-0 +1/64

7.25

-0 +0.015

184

-0 +0.38

WHEEL STANDARDS

  On diagram above Standard Gauge Narrow Gauge
Fractional " Decimal " Metric Fractional " Decimal " Metric
Check gauge "C" 6 15/16

-0 +1/32

6.938

-0 +0.031

176.5

-0 +0.79

6 15/16

-0 +1/32

6.938

-0 +0.031

176.5

-0 +0.79

Diameter point "D" 17/64 0.265 6.73 5/16 0.313 7.94
Flange angle "E"   20o 20o   20o 20o
Flange depth "F" 3/16 0.188 4.76 1/4 0.250 6.35
Flange thickness "G" 9/64 0.140 3.55   0.190 4.82
Flange tip radius "H" 1/16 0.063 1.59   0.081 2.06
Minimum wheel width "J" 13/16 0.813 20.64 1 1/8 1.125 28.58
Root radius "K" 1/8 0.125 3.18 1/8 0.125 3.18
Tread coning angle (maximum) "L"   3o 3o   3o 3o
Wheel back-to-back "M" 6 13/16

-0 +1/64

6.813

-0 +0.015

173

-0 +0.38

6 3/4 6.750

-0 +0.015

171.5

-0 +.038

 
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