Waterproof top door for trailer

A trailer comprising a container supported by a wheeled suspension, the container comprising two opposing sidewalls, a front wall, an end wall, a floor, and two top doors for selectively closing a top opening of the container, each top door being hingedly mounted at an outer edge of the top door at an upper rail of a corresponding sidewall, each top door comprising:

• an outer door rail extending along a length of the top door at the outer edge of the top door, the outer door rail comprising an inward face, a retaining lip at an upward face of the outer door rail defining an inward slot, and a lower slot at a downward face of the outer door rail slidingly to receive a sidewall flap for sealingly contacting an opposing outwardly-sloping upper surface of the upper rail of the corresponding sidewall when the top door is closed;
• an inner door rail extending along the length of the top door substantially parallel to the outer door rail and proximate to a transverse center of the container, the inner door rail comprising an outward face, a retaining lip at an upward face of the inner door rail defining an outward slot, and a closure bracket comprising an arm comprising an inwardly projecting upper arm ending at an elbow and a forearm projecting vertically from the elbow and ending in a gasket slot slidingly to receive a gasket, wherein, when the top doors are closed, the gasket of the closure bracket sealingly contacts an opposing surface of the upper arm of the closure bracket of the other top door;
• a plurality of lower cross struts transversely bridging the inner door rail and the outer door rail, each lower cross strut being affixed at respective opposite ends of the lower cross strut at joints with the inward face of the outer door rail and the outward face of the inner door rail, wherein the joint with the outer door rail comprises flanges;
• a plurality of upper cross struts transversely bridging the inner door rail and outer door rail;
• a door panel sandwiched between the lower cross struts and upper cross struts, wherein respective opposite edges of the door panel are slidingly received in the inward slot of the outer door rail and the outward slot of the inner door rail;
• fasteners extending through openings in the upper cross struts and the door panel to the lower cross struts to clamp the door panel between the upper cross struts and lower cross struts, wherein the fasteners and upper cross struts are removable to remove and replace the door panel;
• and
• an end rail transversely bridging the inner door rail and the outer door rail adjacent the end wall, the end rail comprising a lower slot slidingly to receive an end wall flap for sealingly contacting an opposing rearwardly-sloping upward surface of the end wall when the top door is closed.