(April 28, 2016, 9:04 AM EDT) -- CHICAGO — Participants in a “massively underfunded” multiemployer defined benefit pension plan filed suit April 25 against the plan’s trustees in Illinois federal court, alleging violations of the Employee Retirement Income Security Act (Doris Campbell, et al. v. Charles A. Whobrey, et al., No. 16-4631, N.D. Ill.)....