Maybe railways had little to do with it?
My grandparents met and married (1919) in Blackwood, Monmouthshire.
He was from an ag.lab background in Wiltshire; she was from Kent!
Puzzled me for many years as to how and why they would meet in South Wales.
I have the answer now - coal mining!
He and his brothers left farming and initially worked the Bristol coalfields, but then moved to S. Wales when pits closed in Bristol.
Her father couldn't find work in Kent (a promised job as a tram-driver fell through; his fish shop failed), so he ended up tending boilers in the S Wales mines, and then brought his family.
So, maybe Annie's family (father/brother?) could have come to South Wales for the mines?