The New Zealand Railways Magazine, Volume 3, Issue 7 (November 1, 1928)
With respect to loading; if both receptacles be not loaded at the same time, that which is to be loaded first must be supported until the second is full. Where there is a permanent loading place the carriage is brought over a step or block, but when it is loaded promiscuously it is provided with a support connected with it, which is turned up when not in use. From the small height of the carriage, the loading of those articles which are done by hand becomes less laborious.
The unloading may be done in various ways, according to the substance which is to be discharged; the receptacles being made to open at the bottom, the sides or the ends: in some cases it may be desirable to suspend them by their ends, when turning on their own centres they are easily discharged sideways.