to this direction the door 92 will be referred to as the trailing door and the door 90 as the leading door the leading door 90 is provided with side flanges and is attached to a pivot shaft 94 to one end of which is secured an operating handle 96 the shaft 94 extends the full width of the leading door 90 and is rigidly attached to the door so that on operation of the handle 96 the door can be pivoted about the axis of the shaft 94 likewise the trailing door 92 is rigidly attached to a pivot shaft 98 which also extends the full width of the door and has rigidly attached to it an operating handle 100 the trailing door 92 also has side flanges and is provided at each side towards the edge which cooperates with the adjacent edge of the leading door 90 with a latch pin 102 the edge of the trailing door 92 which cooperates with the adjacent edge of the leading door 90 is stepped as indicated at 104 in order to provide a recess to accommodate the edge of the leading door 90 so that when the doors are in the closed position as shown in fig2 of the drawings the bodies of the doors lie in a single albeit curved plane the step 104 is provided with a radiused.