Dining Car Attendant 1928 - 1939 St Pancras?

[70014IronDuke]

Do you happen to know what those specific train companies that ran dining or buffet cars from Euston were in those days?

As @Gloster says, in the years of your interest, trains from Euston and St Pancras were both part of the LMS Railway. However, in practice, both lines in many ways worked according to their former owners, ie the St Pancras route kept many of its Midland Railway traditions, ditto the Euston line kept many of its LNWR traditions. Since your grandad was in the Birmingham area, chances are that any news on jobs going free came from the LNWR 'circles' there, and the jobs would be linked to Euston rather than St Pancras.

This is not a 'cast iron' case of course, and moreover, the Midland had lots of workings and connections to Birmingham. However, these connections were more to Derby (an Leicester) than St Pancras.