I have spent the last few years trying to recreate those sights and sounds in model form. Many Railway enthusiasts are very discerning and can be quite critical if something does not look quite right, so it is important to get any detail just right. Chimneys and Safety Valve Bonnets in particular on the different classes of GW locomotives are not identical, but they mainly share a shape which is distinctive to the GWR, so they must be made true to prototype. Your Editor has asked me to describe how I make safety valve covers—so here goes!

Firstly, I make a cone from some fairly stiff cardboard with the size and shape being the size and shape required for the finished article. See sketches 1 and 2. Care must be taken to make the cardboard cone the same taper as the finished article with the same dimensions at “A” and “B”. When satisfied that the cardboard cone is accurate, I glue it together solidly. After the glue has dried, the cone is cut opened longitudinally and is used as a template for the brass cover. The brass should be at least 16 gauge—but can be thicker. The brass is then annealed, rolled into a cone and the butt joint silver soldered.

The next stage is to flare the top and bottom. The brass cone must be well annealed—it should be initially after the silver soldering.

When the desired shape has been obtained, make sure it fits correctly on to the boiler (and it will after a bit of practice).

The next stage and this is where I cheat—I obtain some half-round bar and silver solder a ring top and bottom to emulate the folded over rims of the full size object.

On most GWR locomotives—but not all—slots will be required in the bonnet to clear the check valves. These should be cut out when the cover fits correctly—not before.