Michael, are you able to give an indication of the curves used andAlways happy to oblige. The minimum radius of the Shimla line was 45
degrees, which I understand is 123ft radius. This compares with the
minimum radius on the VRNG, which was 2 chains, or 132ft.
Most of the locos I've seen seem to be a little narrower - about 7'6"
but overall size about the same. So maybe a slightly smaller loading
gauge. For the Shimla 2-6-2T locos:
Wheelbase Rigid 6'
Wheelbase overall 17'6"
Weight total 34.97
Max axle weight 8.55
For a VR NA:
Wheelbase Rigid 8'
Wheelbase overall ?
Weight total 35.3
Max axle weight 9.2
So there is not much difference. The Shimla loco acheves a greater TF
despite being a fraction lighter, probably because of better
distribution of weight.
Rolling stock is almost univerally smaller than the locos, and most
Indian designs I have seen are 7' wide.
I suspect that in other cases the gauge chosen was for more arbitaryAnd for industrial lines I've came across a huge variety of gauges.
There do seem to traditions - for 2'6" gauge in Britain, peat railways
(one built as recently as 2000), military instilations, gasworks, and
others , in Pensylvania steel milla and coal mines, in Lousianna sugar
lines. There seem to have been a "nest" of 2'6" logging lines around
the Erica district.