Thank you! I have a few ideas for the next article. Locomotives are up there on the list, but they are the final challenge of steam engineering, there is so much to cover.

Also considering the origins of precision - the intertwined evolution of machining tools and measuring systems that allowed these machines to be built.

RE: 3 year old - yes, mechanical systems are wonderful for children (and adults). There is something incredibly satisfying about watching them in motion doing work.