There are many good websites about how to restore toy steam engines so I won't go into too much generic detail just as to specifics for Australian brands. For a general soldering guide have a look at 'Mamodman's' Website. Just be aware that a number of Australian toy steam engine's boilers are made from rolled sheet not tube so its best avoided if at all possible opening up the boiler.
Below I'll give drawings and hints and tips to Australian models which will slowly grow over time.
Renown engines
For some reason I see a lot of Renown engines missing the bushes for their safety valves and whistles. Click here for the dimensions to make a new bush
16/4/08 I now have my lathe and I've started to produce some small parts for Renowns. I can now offer overflow plugs and bushes, safety valve and whistle bushes. Springs for safety valves and trunnion bolts, filler bolts which can also be used to replaced lost or damaged whistles and safety valves. I've yet to work out pricing for these parts but contact me if your interested. I also hope to make drawings for these parts so people whit lathes can make their own in the future.
Renown Windmill A fellow collector is in the process of restoring a Renown windmill and in the process is drawing up a great set of plans of the parts and he has kindly given me permission to make them available here in pdf format. Thanks Bryce. Windmill Blade Assembly Base Plate Top Half of Windmill Assembly