What is the boiler pressure

[Michael CallaghanParticipant @michaelcallaghan68621]

Hi, can anyone please let me know the correct boiler pressure for a 2 1/2 inch gauge Dyak please.

[Nigel Graham 2Participant @nigelgraham2]

If you can’t find a definite answer for the design, Martin Evans’ Manual of Model Steam Locomotive Construction recommends 70psi for a 2.5″ g. locomotive. Which seems high but probably necessary for hauling a full-size driver behind it.

Is this for building new, or putting an old model back into service? If the latter and the pressure-gauge is not marked (as it should be), I would take that as a maximum and carefully consider the condition of the boiler; if necessary down-rating it.

If new, the drawings should specify the w.p., surely?

If you intend public running, even if the “public” are fellow model-engineering society members, it will need testing and the boiler inspector will need know the designed (or if down-rated, new) working pressure.

[WearyParticipant @weary]

80 lbs sq in.

(Curly’s ‘standard’ pressure)

Sample Reference.

Regards,

Phil

[Michael CallaghanParticipant @michaelcallaghan68621]

Thanks chaps, I think given the age of the boiler 70 psi would be best.

[Author]

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