No. 81-2475. Argued April 2, 1982. Decided April 13, 1982. William J. Wade (argued), Richard G. Elliott, Jr., Richards, Layton Finger, Wilmington, Del., Ray J. Schoonhoven, Valerie J. Hoffman, Douglas A. Darch, Seyfarth, Shaw, Fairweather Geraldson, Chicago, Ill., for appellant Delpro Co. Erick J. Genser (argued), Edward J. Hickey, Jr., Michael S. Wolly, Thomas A. Woodley, Mulholland Hickey, Washington, D.C., for appellee Brotherhood Railway Carmen. Joseph J. Farnan, U.S. Atty., Wilmington, Del.