This subject does come up from time to time and I don't think it has ever
been satisfactorily resolved, or ever will be. With an edge railway the
track gauge is crucial but there is no such crucial dimension on a plateway.
My feelings are to measure across the wheel tread centres or 'track' in
motoring parlance. In Cornwall there is a cast iron plateway turntable
surviving. It is one solid casting so there is no doubt as to any of its
dimensions. The 'track', as worn in the flats of the plate by the wheels
was exactly 30 inches, whereas every other dimension across the flanges or
across the flat of the L, was an odd figure involving fractions. Other key
dimensions, the diameter of the plate and the square base it sat in, were
all exact inches also.
To me it is clear that the man who made it, whether foundryman or engineer,
envisaged the trucks as having a 'track' of 30 inches, a good round
figure, and would not have messed about with odd dimensions involving
fractions.
Michael Messenger
At 00:20 04/07/03 +0000, you wrote:
>How do you measure the gauge of plateways, both now and in the past? I am
>aware that one school of thought says that one measures from centre to
>centre of the actual track of the wheel on the plate, though given that
>plateway wagon wheels were free to slide on their axles, this could vary a
>lot! An example I came across recently by the German engineers Von
>Oeynhausen & Von Dechen, relating to the Tavistock Canal incline in 1827,
>seems to have been measured between the upright flanges of the L section
>plate rails. Thus when one measures between wheel centres, one gets a
>higher figure. Any answers please?
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Michael Messenger
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