Interesting that you mentioned a Greek myth, I have a started piece that I kind of lost my way with, about a person who was the reincarnated soul of Odysseus and through a blow to the head whilst been mugged, his past life comes to him, and the trail of him getting home becomes also the events of the Odyssey though in a contemporary setting, as though Poseidon is still punishing him, cursing him to instead of escaping his anger, relive it through the myriad of lives thereafter.
I think you are brave taking on historical writing, it requires so much initial leg work, the advantage clearly of total fiction is the ability for it to be spontaneous. I am more of a “let the character loose upon the page” kind of writer, though I have a rough A-Z idea of the story, it invariably detours all over the shop. Did you find that you had to plan everything out to ensure that you weren't just shouting facts at the reader, certain genres can be difficult to balance the narration, with technical/historical hyperbole.
I was part of small informal group who would write nano fiction, 1500 words and the winner from the previous month would start the piece or give a start that had to be either featured or clearly the root source of any inspiration.
That made for a fun exercise too, as it forced to try in terms that you might not initially do yourself to begin with. That and 1500 words is nought and therefore each one becomes precious. I was forced to raise to the occasion in some instances and that is always a good thing, I know from experience, that there is a danger in not exposing your writing to others, it can hamper your development to my mind. Hence why I am here I suppose.
On your comment on the themes, is it that you are looking to do just that, the decline of the carriageways to rail could have many relative parallels which you could use in another time period. So was it the specific theme and substance of that which made it such a potent period in your mind, or perhaps some other ancillary interest that happened to complement it?
I only ask because I would have believed that any themes would be transmutable to just about anywhere, and if the one you chose was difficult, it could easily enough be done elsewhere. Whereas despite the extra work you stuck to it. I just wonder why that was?
Also I sense a clue in your Avatar...