Thanks to those of you who assisted with expert commentary on the completion of the Severn Valley Railway, and other information. I didn't realise that folks would be so amazingly keen to help, otherwise I would have provided more material initially! Here is some more of the intriguing story I already have.....incidentally we should not think that our ancestors didn't move very far. Even poor people were pretty mobile, at a time of huge social change in the mid nineteenth century.
After giving birth to her baby Robert Smith Grant in Market Drayton in November 1866, Elizabeth returned with him to Leicestershire, where she left him with the Coleman family, former neighbours of her family in Great Glen, to be fostered whilst she worked elsewhere. She married one John Turland, in October 1869, and after a few short stays in various mining villages in the western part of the county, they moved back into the centre of Leicester. Robert lived with the same family in Great Glen until he was at least 14. He was my great grandfather, and had an interesting life himself.
Elizabeth's mother Judith, and her husband John Wood(s) (who may not be Elizabeth's father; they married some years after she was born) did move away from Chelmarsh, Shropshire, presumably after his employment on the Severn Valley railway was finished. Judith is next found living in Nuneaton in 1871, and her husband is elsewhere, presumably still working on the railway or something similar. By 1881, Judith and John are back in Leicester, living in a slum property in the centre of town with Elizabeth, who by this time has married, had two girl babies (both of whom died of fever and diarrohea), and whose husband had by then left her. Our ancestors faced some tough times and tragedy, as we know. After Judith died, John Wood (by then a drunk) committed suicide by drowning himself in the canal close to where they had lived.
Back to Elizabeth. At fourteen, in April 1861, Elizabeth Grant was working as a servant close to her family home in Leicestershire. Both her grandparents, with whom she had spent her days as a child in Great Glen, were by now dead. The point about young unmarried women choosing somewhere to have their baby where they would not be known is well made. But it seems strange for nineteen year old Elizabeth Grant to choose Market Drayton for her baby's birth, if she had no connections there at all. She was certainly not wealthy. The birth certificate for Robert Grant does not show a father, and nor does the christening record. Elizabeth did give Robert an uncharacteristic 'middle' name - Smith. In later life this name was 'lost', until it reappeared several weeks after Robert Grant died in 1945, when it was added to the death certificate. I am guessing that 'Smith' might have referred to his father, but that's uncertain. It's a very common name, of course, and Elizabeth would have encountered several male Smiths in her life.
Thanks to the person who suggested consulting the bastardy register - I will try to explore that if I can ever get to the Shropshire Record office when it is actually open!
However, I'm still wondering if Elizabeth Grant (born 1847 in Leicester) was working as a servant or in other occupation somewhere in Shropshire in the mid 1860s. Any more ideas on that, folks?