In action by plaintiff-union seeking reversal of Nat’l Railroad Adjustment Bd. order that imposed earnings-offset on back-pay award given to railroad employee, Dist. Ct. erred in dismissing union’s petition for review and remanding case back to Bd. to make finding as to whether employee had any actual earnings. Established Bd. practice required that parties make any earnings calculation, and effect of Dist. Ct.’s order was to essentially change said practice where legality of said practice was not challenged. Ct. further observed that it was doubtful that there was any basis for striking down Bd.’s calculation of earnings offset where scope of review of Bd.’s order does not include issue as to whether Bd. erred in interpreting applicable contract.