The first group of rail buses, of which FP1 was the first, were built in 1937 to an overall design of the NSW Railways' Road Motor section, by coach-building firm Waddingtons Pty Ltd, Granville.
The rail bus concept was intended to provide a passenger service on minor branch lines where the available traffic did not support economic use of a conventional steam-hauled passenger or mixed train, or even a rail-motor service provided by one of the relatively new '42 footer' CPH 'tin hare' motors. FP1 entered service on 7 July 1937.
It appears that the rail bus concept was less than successful because all were withdrawn from passenger service, to be used as pay buses, within a year or two of their commissioning.
