There will be a rich , unwritten seam from ex BR members here.
Grades were 1 -5 for Clerical Officers , A to D for Supervisors and MS1 -5 for managers. Senior Officers went from EG (or SO) 1 to "unclassified" - but there were not many of those. Technical departments were different.
A "Traffic Management Trainee" in 1979 got £3700 per annum plus travel and LT (as it was then) priv rate. We got an all stations BR standard class for the training period , to encourage us to go out and about as much as possible - some were stamped "available also in brake vans and rear cabs" The wage then was reasonable , but the job was much coveted. About 30 that year , and I regret to say the dropout rate was quite high - some not making it beyond 12 months. There were staff entrants , and another course based on "Traffic Students" -which was part College time and part BR training.
When you qualified , you were promised a supervisors role - usually a C or if lucky a D - these jobs entailed anti-social hours , weekends of course - direct on calls and a launch into the real world of bad weather and direct staff relationships. Quite hard after the university period and "cushy" training when you swanned around , learned a lot (sometimes not) , and had no direct responsibility.
Everyone wanted an MS1 for the 1st class travel , (an MS2 gave you a Regional Pass which you could change on geographical location) , BUT - you made lots of money in supervisor jobs with overtime etc , and management was pretty much "flat time" - plus you did unpaid overtime - every job description has "and any other duties as requested" - as a "C" I did 5x12 Mon-Friday , often a 0700 - finish on Saturdays , and too many Sundays. Ergo - lots of money and no social life.
(when I moved to London as an MS , I doubled my mortgage for a similar property , but for 6 months I did some "extra" work outside the railway to get over the loss of earnings.
As time went on , the railway cut back on "starter" jobs - so junior Assistant / Station Managers were culled and so on in the "on the way out" regions Even "smalled" areas went (Marylebone being only an MS1 pre modernisation)
Could really write more - but this is a flavour.