Scale narrow gauge locomotive

I am just planning the building of a narrow gauge Beyer Peacock Garratt, I have a full set of original drawings, The full size loco gauge is 2ft or 610mm, I want to scale the size to run on 5inch gauge, can anyone tell me what the scale should be, is it 1.0625 per inch ?

The drawings are for a South African Railways 2ft gauge Garratt.

Scale would be 2.5inch/foot (2ft gauge gives 5inch gauge) or about 1/5 full size and ignore the inaccuracy in the gauge.

I suggest you choose a scale that's easy to work with and modify any critical dimensions to suit. That's what i've done with a 3ft6in gauge loco for 5inch gauge which i am making at 1/8 full size or 1.5inch/foot scale. The scaled gauge works out to be 5-1/4 inches so my wheels are a fraction closer together on the axles than they should be, but as long as you design everything else to suit then it's not a problem. Model railway manufacturers have been doing it for decades .

Thank you Geoff

I was having a senior moment when trying to work out the scale, you have confirmed what I thought, I got 1/4.8 full size. I started drawing it from my plans then realised just how big it will be, thats when the doubt crept in. Its a 262-262 wheel layout, It works out that each set of frames will be 37 inches long, overall lenght will be about 11ft. Fortunately I do have room to build it and the machining capability although it is too long to fit on our club turntable.

It will be electrically driven as the boiler cost is to expensive even if I make it myself, I am in a lucky position in that one of my close freinds is a pattern maker and another friend has a non ferrous foundry so I can getting castings made quite easily.

That will be a pretty massive beast when finished! Should have tremendous pulling power too. One of the problems with modelling narrow gauge locos from the colonies is that they were generally built closer to standard gauge proportions, so when scaling to suit the gauge it ends up a big model. A standard gauge loco at 1:4.8 scale would be about 12" gauge. Good luck with your project.

Did this project idea progress any further, I'm a big fan of Garretts,and especially their sheer size in full scale, the narrowgauge loco will be one heck of a beast when built

There is a running full size one where I live - its huge