What Story Do You Think You're Writing?

'Arthur's Tractor', written by Pippa Goodhart, and illustrated by Colin Paine


I began writing the story that became 'Arthur's Tractor' with a simple aim; to capture some of the fun of mechanical sounds that I remembered from The Little Red Engine stories (by Diana Ross and Leslie Wood) of my own early childhood.  I couldn't have told you what happened in the stories, but I did remember the joy of those repeated 'CHUFFA CHUFF' train noises, and the 'WHOOEEE' whenever anything exciting happened. 
Funnily enough I came across 'The Little Red Engine Goes To Market' deep in a box of dusty books just yesterday as I was unpacking them onto the shelves in our new house.  There are other sounds in the book which I hadn't remembered - 'And it drew up at at the platform SHUUUH'.  Going uphill made the engine go HUTCHA BA HUTCHA BA HUTCHA BA BAAAA'.  And there are animal noises too.  What there isn't is much of a story; simply a journey recorded, animals collected and taken to market, and then home to the shed/bed. 
Anyway, it was those kinds of sounds that I was after, and I chose a tractor as my vehicle.  Arthur, the farmer, came into my head from I don't know where, and we were off -'Arthur's tractor ploughed up and down, turning green to brown.Chugga thrum, chugga thrum, chugga chugga thrum ....'And before long we've got an 'Eeeek!' that makes Arthur stop his tractor, turn off his engine and get down from his cab.  He stands for a while, and he scratches his head, then he siad, 'That must be the sprocket spring sprigget needing a twist and an oil', so he twists and oils, and gets back on his chugga thrum way before another sound repeats the process.
The much more DRAMATIC story is happening behind Arthur's back, unnoticed by him.  The 'Eeek!' is actually coming from a princess being faced with a dragon.  Then the 'THUD THUD THUD' comes from a prince arriving on a horse, etc.  The fun, I hope, for a child is in knowing what the narrator, and Arthur, apparently don't know, because, of course, even very young children can 'read' pictures.
Arthur's and the fairy tale stories come together at the end when Arthur's plough blade breaks.  Arthur then uses the prince's sword, welded with dragon breath, to mend the blade.  And this is where the question of 'what story do you think you're writing?' comes in. 
It was only some time after the story was written, and when it was on it's way to publication, that it dawned on me (duh!) that what I'd done in this story was to literally turn a sword into a plough share.  Clearly that Biblical message towards peace rather than war was imbedded in me, and had come out in literal form.  This is the only one of my stories to end with the cliche of 'they all lived happily ever after'; a nod to the fairytale ingredients I'd used, but also because the characters have now all paired-up into happy friendships.  They've achieved peace.
But something else was going on subconsciously too because, at the end, Arthur makes friends with the princess who is called Edith.  Arthur and Edith were the names of my paternal grandparents who I never knew.  Of course I was aware of that as I used the names, but I hadn't consciously made the link with their son, my father.  My father was a man who worked in a very practical way to bring peace rather than war to the world.  He became the President of the International Court of Justice in the Hague; an institution which few are aware of (it's nothing to do with the International Criminal Court), where boundary disputes are considered and resolved, bringing peaceful solutions to such problems.  And that is why I dedicated 'Arthur's Tractor' book to my father. 
So a story intended to simply enjoy some mechanical sounds, along with a bit of visual trickery, wrote itself into being, if you like, a book about peaceful resolution to conflict.  That surprises me!
Have any of you found stories writing themselves into something different from the story you thought you were writing?