1. IN A RAILWAY HOPPER CAR HAVING A ROOF WITH AT LEAST ONE ELONGATE HATCH OPENING THERETHROUGH, A HATCH FITTING EXTENDING ABOUT SAID OPENING AND PROJECTING UPWARDLY FROM THE ROOF, A RELATIVELY FLEXIBLE ELONGATE HATCH COVER FOR THE HATCH OPENING MOUNTED OVER THE HATCH FITTING FOR MOVEMENT BETWEEN OPEN AND CLOSED POSITIONS RELATIVE TO THE HATCH OPENING AND HAVING A PLURALITY OF UPWARDLY PROJECTING, GENERALLY PARALLEL RIBS EXTENDING LONGITUDINALLY FOR SUBSTANTIALLY THE ENTIRE LENGTH OF THE ELONGATE HATCH COVER, A PAIR OF SPACED, PARALLEL STIFFENERS EXTENDING TRANSVERSELY OF THE COVER ACROSS THE UPPER SURFACES OF THE RIBS AND SECURED THERETO, AN ARM OVER EACH TRANSVERSE STIFFENER IN VERTICAL ALIGNMENT THEREWITH AND PIVOTALLY MOUNTED ON THE ROOF FOR MOVEMENT BETWEEN OPEN AND CLOSED POSITIONS, A SPACER BETWEEN EACH ARM AND THE ASSOCIATED TRANSVERSE STIFFENER CONTACTING THE ASSOCIATED STIFFENER GENERALLY CENTRALLY OF THE WIDTH OF THE HATCH COVER AND SPANNING AT LEAST A PAIR OF RIBS BUT TERMINATING SHORT OF THE HATCH FITTING WHEN THE COVER IS CLOSED, MEANS CONNECTING EACH SPACER AND ASSOCIATED STIFFENER TO THE ADJACENT ARM AND PERMITTING A LIMITED MOVEMENT OF THE HATCH COVER RELATIVE TO THE ARM IN A DIRECTION TRANSVERSELY OF THE HATCH COVER TO FACILITATE SEATING OF THE HATCH COVER ON THE HATCH FITTING, THE COVER BEING PRESSED DOWNWARDLY AGAINST THE HATCH FITTING WHEN IN CLOSED POSITION BY THE ARMS AND ASSOCIATED SPACERS ALONG AN AREA OVER THE HATCH OPENING TO OBTAIN A RELATIVELY TIGHT FIT AGAINST THE HATCH FITTING, AND MEANS RELEASABLY HOLD THE COVER OVER THE HATCH OPENING IN THE CLOSED POSITION THEREOF.