The "No. 19" Boiler.
I call it so because it is a combination of No. 12 and No. 7 in the Swindon classification. The smokebox and chimney are as on the King class, but the barrel has a hump instead of an even taper, the safety valve being set on the highest point. I found on previous G.W. engines I have built that, owing to the valve being set on the barrel and close to the water level, there was a tendency to prime when blowing off. This boiler barrel was intended to minimise the trouble, yet retain the G.W. flavour; so the taper extends from the smokebox to the valve, which is perched on the highest point, and from there to the firebox the taper is in the reverse direction. It is not very apparent in the picture, but the effect in the actual engine is quite good and adds to the general "massiveness". As the firebox cannot be very deep on account of the trailing axle, the foundation ring rests on the frames and the grate is the full width between, less thickness of plates. This arrangement, combined with a box 4½ ins. long inside, will provide ample steam for the big cylinders — providing, of course, that admission and cut-off are correct — without undue forcing. All the usual fittings and top works will be provided; the cab will be of the older pattern with short roof and no side windows, to facilitate handling, and a latest Swindon type high-sided tender is also in hand.
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This page was last changed on 04/05/2016