Narrow Gauge - how is it measured?

[eMeS]

My query stems from a recent visit to the Vale of Rheidol railway, and where at Devils Bridge station, I was able to measure the gap between the rails, but I'm guessing I was wrong with my measurement.

Wiki says it's 1 ft 11 3⁄4 in (603 mm), but how is this measured, and what are typical tolerances?
1 - distance between rails?
2 - distance between outer wheel flanges?
---
Is standard gauge measured in the same way?

Many thanks

 

[Llanigraham]

Between the rails.

 

[edwin_m]

There's an official standard (no pun intended) somewhere, which says something about measuring between the inner faces of the rails at a level of 13mm (I think) below top of rail. However this is for standard gauge and narrow gauge may be different as it generally uses a smaller rail section.

Tolerance on gauge is surprisingly wide, at least in respect of broad-to-gauge track, but I don't have any figures in my head.

 

[fsmr]

We run 10 1/4" gauge nominal inside edge of the rail but this can become greater (gauge easing) on tight curves to reduce flange wear , and also allow our larger 4-8-4 and 2-8-4 locos through the curves, this obviously cannot be to the extent that the loco or coaches axles drops through
As we use treadle axle counters for sections and not electrical track circuit, (only for reference not protection) we can weld in steel tie bars to maintain and accurate gauge without relying on sleeper spikes


Interesting subject gauges especially how Stephensons standard gauge became the norm for 60% of the world at 4ft 8 1/2"
Not even 4 foot 8 or even 5 foot let alone Brunel's visionary broad gauge
Hope that explains it

 

[CarltonA]

The narrow gauge Soller Railway in Mallorca has the strange gauge of 914mm, strange that is until you convert it into imperial. Yup, it's 3ft.

 

[zn1]

the distance between the running rails..........

 

[gordonthemoron]

I thought Stephenson's standard gauge became the norm because Robert built so many railways? In anycase, didn't Stephenson get the gauge from pit wagons/roman chariots?

 

[DarloRich]

Q) Narrow Gauge - how is it measured?

A) They send out the NMT (Narrow gauge Measurement Train)

Sorry!

 

[Ploughman]

Narrow Gauge - how is it measured?

With a NARROW GAUGE

 

[341o2]

I thought Stephenson's standard gauge became the norm because Robert built so many railways? In anycase, didn't Stephenson get the gauge from pit wagons/roman chariots?

I thought the origin of the British standard guage was because ancestor of the railway was a "plateway" or "waggonway" where the "rails" were L or U shaped to accomodate road carts.

there is a survivor of this era at Haytor in Devon where the rails consist of channels carved into granite blocks, even pointwork.

the width of wheels on a road cart was 5 feet, so when railways evolved with flanges on the wheels rathe than the rails, the rails were now 4ft 8 1/2 inches inner face to inner face.

with wide wheel treads to compensate for poor track especially found in industrial narrow guage, in practice 1ft 11 1/2, 2ft and 60cm stock worked quite happily over the same tracks