Garden Railway Forum

I plan on running 'Anna' and 'Victor' at a few places, but I believe with the higher boiler pressures I need to get them tested by the 16mm NGM (which I will join in due course) so that they are deemed 'fit for use' and fall under their third party public liability insurance.

Is this right?

I've recently joined the 16mm NGM, and you do not get a copy of any Association rules, or information about their Insurance cover.

So you need to go to their website (and it refused to work several times for me just now), and look at the Insurance conditions - http://www.16mm.org.uk/membersindex.htm

Both your locos should be well below the 3 bar-litre limit so it is not a requirement to have the boilers tested, but rather a recommendation.

The 3 bar-litre limit is defined as the internal volume of the boiler (in litres) multiplied by the working pressure (in bar), where 1 litre = 1.76 pints and 1 bar = 14.5038 psi.

Looking at my MSS instructions this gives Volume as 120cc and max working pressure as 0.7 bar. The uprated safety valve should be no more than 25PSI, which is about 1.72 bar. So Victor is well below the 3 limit.

You should be able to work out the figures for 'Anna'.

Thanks Chris

Anna blows off at 3.5 psi below the 3 bar limit, next time I fire her up though I will check again as to what pressure she blows off at

Remember it is a 3bar-litre limit, so it blows off at 3 bar, it would need to be over 1 litre in volume to exceed the 3 bar-litre limit.

I would guess 'Anna's volume is no more than about 1/3 of a litre, given that the Mamod/MSS is only 0.120 of a litre.