I've managed to destroy the smoke generator in my Hornby D49 Cheshire while trying to fix it. They seem a little temperamental and rather fragile. I think it's the same unit as used in the 28XX GWR 2-8-0?
I'd guess that the Seuthe ones are better, but they are wrong shape. The usual Hornby spares people don't seem to carry Hornby ones anymore. Anyone got any ideas of any other unit I could fit?