Driver Hierarchy at Companies

When I first started at Stirlands in the mid 80s there was a procedure for jobs amongst drivers they were
Night Trunkers
Spare Night men
Night Shunters
Day Trunkers
Day men
Day Shunters
Roamers(Trampers)
When you started you were either put on spare nights or days
All new jobs were advertised on the board and each job was allocated down to seniority and suitability
I was wondering if any other firms operated a similar system or how did jobs get allocated