5" gauge - minimum track radius

Does anyone have any info on the minimum radius for a curve on 5" gauge track versus the length of a locomotive's (fixed drivers) wheelbase?

thanks.

 

Hi

The best thing to do is join the Miniature Railway World Forum and ask the same question.

Alex

 

It depends....

There is a mathematical formula for working in out but you need to know a few details first. I won't bore everyone with the maths

First you need to decide some basic principles apart from the wheelbase

Wheel profile (flange depth)

Sideplay of the wheelsets

Widening of the gauge

Speed of operation

How often you want to reprofile the wheels or change rail (depands on material)

As a general rule at low speeds an 0-4-0 with normal profile wheels can get round a minimum 12ft radius, this is uncomfortable and will create wear, if you use aluminium rail you will find neat little shavings along the inside of the rail head. (I've got an bucket full, anyone want any...) Gauge widening helps but this radius is only recommended if you have no alternative and definitley not on any public line.

From 15ft up you can get round a short wheelbase 0-6-0 under the same conditions above

From 20ft upwards you will get round (carefully) most 0-6-0 locos

Ideally for a general line 25ft radius and upwards will cope with almost anything

35ft upwards should be considered for continual running and if your ambiations are in the Big Boy league. The 5" Big Boy mentioned on here will go round the 37ft radius curves on it's home track.

Hope that helps

 

yes, very helpful.
I might be being unrealistic dreaming about a 5" GWR King ! - Perhaps a Pannier or Prairie - maybe a Manor at a stretch is more realistic.

 

Why is guage widening not recomended i know or a fact that in the Bigger and in my eyes slightly better relams of 7 1/4 it is standard its only like a eight of a inch or so though

 

What I tried to say was that the radius of 12ft is not recommended. Gauge widening is fine but beware the day that someone comes along with a fine-scale model with a 'thin' wheel profile and you might find that it sits very neatly inside your gauge widenend track. Been there...