Thousands of jostling traders once packed the floors of Chicago’s futures exchanges, before the advent of high-speed computerized trading turned them into relics of a bygone era. Now, some of them will finally have their day in court.

On Monday, a trial is set to begin in a long-running class-action lawsuit filed by traders who say that exchange giant CME Group duped them out of the privileges they held as members of the city’s once-elite community of floor traders.