Diggie,
I take it that I can ask to see the archives you mentioned e.g the employment records for the railways, without any issues if I went up to PRONI?
Dunno, I never accessed them yet!
[Shouldn't expect any problem, but you could always EMail/Phone PRONI beforehand.]
When PRONI was set up in the early 1920s, it had a building with lots of empty shelves. Its staff, no doubt inspired by the sad results for cultural and family history of the recent events in Dublin, were instructed to go out in to the field to search out records of all kinds, with a view to persuading their owners to allow them to be handed over.
[N.B. The railway companies then were all private business enterprises, established by public subscriptions, not owned by Government.]
It was considered essential for success in life for all prospective entrepreneurial "Gentlemen" of the day to be formally educated in three essential skills - Sanitary Engineering, Railway Engineering and Political Engineering!
James CHAINE (of Ballycraigy, Muckamore and Ballycreggy, Larne) was a key shaker and mover of those Victorian times, losing three fortunes before making a fourth.
Best of luck onward.
Capt. Jock [Trawler of the murky depths ...]