PRONI hold some staff records for the Northern Counties Committee (LMS) who operated the railway from Belfast to Londonderry via Limavady Junction.
UTA/11/K/2 contains records for 1869 – 1903
UTA/11/K/3 contains the records for 1899 – 1911.
Typically it shows when people were moved from location to location, demotions and promotions, some disciplinary issues (mostly drink related, in my experience), their wages and why and when the person finally left the company’s employment.