Doorpost locking arrangement for railway cars

Claim 1

IN A RAILWAY CAR HAVING A FLOOR, A ROOF STRUCTURE AND END WALLS ARRANGED TO FORM AN OPEN SIDE RAILWAY CAR, A ROLL-UP DOOR DISPOSED IN SAID OPEN SIDE, AND A ROLL-UP DOOR TRACK FIXED BETWEEN SAID ROOF AND SAID FLOOR FOR GUIDING ONE END OF SAID ROLL-UP DOOR; THE IMPROVEMENT COMPRISING A REMOVABLE DOOR POST EXTENDING VERTICALLY BETWEEN SAID ROOF AND SAID FLOOR AND SPACED LENGTHWISE FROM SAID FIXED DOOR TRACK, SAID REMOVABLE DOOR POST HAVING A DOOR TRACK FOR GUIDING THE OTHER END OF SAID ROLL-UP DOOR, LOCKING MEANS FOR POSITIONING SAID REMOVABLE DOOR POST, SAID LOCKING MEANS COMPRISING A LOCKING BOLT MEMBER, GUIDING MEANS ON THE LOWER END OF SAID DOOR FOR GUIDING SAID LOCKING BOLT MEMBER IN VERTICAL SLIDING RELATIONSHIP, AN OPENING IN SAID FLOOR ADAPTED TO RECEIVE THE END OF SAID LOCKING BOLT MEMBER SO THAT SAID DOOR POST MAY BE LOCKED IN SAID OPERATIVE POSITION,NOTCH MEANS IN SAID LOCKING BOLT MEMBER, LOCATOR MEANS FOR ASCERTAINING THAT SAID DOOR POST ASSUMES A SUBSTANTIALLY VERTICAL ATTITUDE IN SAID OPERATIVE POSITION AND INCLUDING A LOCATOR BOLT DISPOSED ADJACENT TO SAID LOCKING BOLT MEMBER, MEANS ADJACENT THE UPPER END OF SAID DOOR POST FOR GUIDING SAID LOCATOR BOLT FOR VERTICAL SLIDING MOVEMENT, A LOCATOR BOLT OPENING IN SAID ROOF STRUCTURE ADAPTED TO RECEIVE THE END OF SAID LOCATOR BOLT MEANS, SAID LOCATOR BOLT MEANS INCLUDING MEANS SEATABLE WITHIN SAID LOCKING BOLT NOTCH, AND LOCATOR BOLT STOP MEANS MOUNTED ON SAID DOOR POST IN THE PATH OF MOVEMENT OF SAID LOCATOR BOLT MEANS FOR RETAINING SAID SEATAGLE MEANS SEATED WITHIN SAID NOTCH AND THEREBY PRESENTING THE INSERTION OF SAID LOCKING BOLT MEMBER INTO SAID LOCKING BOLT OPENING UNTIL SAID LOCATOR BOLT MEMBER IS INSERTED INTO SAID LOCATOR OPENING.