FGW (LTV), works a 3 week cycle: We,Th,Fr, Sa,Su*,Mo,Tu,We,Th,Fr,Sa,Su*,Mo,Tu,We,Th,Fr,Sa,Su,Mo,Tu,
Red=work, Blue=rest days
Works out as 4 working days/week + 1 Sunday in 3 paid as overtime (optional but someone must volunteer to cover else you have to work it as per the roster). Evens out to exactly 35 hrs/week over the course of 2 pay cycles (8 weeks), seldom more than an hour either side of 35hr/wk taken in isolation.
*either may be rostered, depending on whether one is switching from earlies to lates or vice-versa. Almost unheard of for people not to have a Sunday uncovered by a willing O/T volunteer, I know drivers who've never worked a Sunday in years. Sunday isn't counted as part of the working week for hours (and thus, importantly, pension)
Generally one works a week of earlies, a week of 'mids' (as I call 'em - generally ~09:00-18:00), and a week of lates. Some choose to request permanent earlies or lates, which can be 'socially convenient', and/or an aid to doing predictable overtime.