The inside of the loco body, with the boiler weight removed. The weight fits over the upright which holds the light bulb. The screw through the boiler dorr tightens against this, effectively trying to pull the weight forward

Position of the screw to hold the body in place.

The boiler door is often missing on 2nd hand locos. Or people have made up their own, which suggests that over time it comes loose and falls out.

Note the two holes at the bottom for the light to emerge. This is the correct orientation. If your boiler door is slack enough to make you worry about it falling off, then take a narrow strip of paper. Narrower than in the photo, which is exaggerated for purpose of demonstration. Lay it across the top of the boiler and fit the cap. It will be nice and tight. If it is still not tight enough, make the paper wider - not thicker.

Now with a black ink pen, or roller ball, draw thick black lines on the paper around the boiler. Go mad with this - the purpose is to make the paper wet and soggy, as well as to make it black. The paper will then tear off easily leaving an almost invisible edge.

If necessary, use your thumbnail to smooth off the edge of the paper.

Use the coupling rod to hold the pin above the hole, and then gently press it in with the flat end of a small screwdriver, or a thumb.

All back together again. Except the valve gear ! I do not have a photo sequence for the valve gear - but take a look at the pages for the Ivatt 2MT 2-6-0 with tender. When I get round to doing them.