An all-star team of defense counsel led by Sidley Austin’s Carter Phillips derailed one of the largest pending antitrust class actions in the country on Friday when the U.S. Court of Appeals for the D.C. Circuit denied class certification in a case alleging that the largest freight railroads in the U.S. conspired to fix prices.

The case raises a thorny class action question: When can a class action include uninjured members? How many is too many?