Railway Express was owned by the railroads and I'm guessing that non-owning roads could still participate in the Railway Express business. From 1960 Moody's these roads still were carrying passengers but did not have any ownership in REA: Chicago & Northwestern, Monon, Grand Trunk Western, Central Vermont, Long Island, Ft. Worth & Denver (but Colorado & Southern and Burlington-Rock Island were owners). But you probably could ship a package anywhere on those lines where passenger trains went from some point on a road that was an REA owner. Interestingly, REA had an Air Express division that utilized airlines, but REA had no airline owners. REA also utilized water carriers though by this time probably the only user was the Old Bay Line, a railroad subsidiary. REA also had a trucking subsidiary that specifically did business in Indiana only where passenger trains had been discontinued.