Hello Billysiv and welcome to the forum. If your Grandfather was employed at Saltley before WW1, he would have been employed by the MIDLAND Railway. This became part of the L.M.S. at what was called "The Grouping" at the start of 1923. It is my understanding that surving records are held at the National Archives, Kew. Someone else on here may be able to help with Reference Numbers, etc.
Good luck with your research, I hope you get on better than I have, I'm totally stuck trying to sort out my Mother's Grandparents!
Regards, 62440.
