Typical USA seniority style using a PBS computer system.
Schedules are awarded in seniority order based on preferences as entered in the computer. Lots of preferences available, lots of ways to mess it up, steep learning curve.
We have pairings from day turns to four day trips to choose from. You must bid at least 70 hours, max is 95 (per calendar month). Senior bidders can fill their month in 12 days easily, junior may take 15 days.
Then there is reserve...