I just saw a bit of ‘How it’s Made’ on Discovery (1/11./10) which promised a ‘garden steam locomotive’. It’s a Maxitrak 0-4-0 and the programme is on Discovery+1 at 9:30pm.
It’s hugely oversimplified and focuses on just a few operations – they show something of machining the slide valve, and then give the same time to the entire chassis. they also make out that cleaning soot out of the flues after a steam up is checking them for blockages after assembly!
But it is interesting, not least for showing how relatively simple the construction of a commercial loco is compared to most of the designs in ME.
Final thought, they need to beef up the whistle bracket!
Neil