 This designation was wholly unrelated to the steam locomotive A class of 1873 or A class of 1906.In the 1910s, NZR began experimenting with railcar technology to cater for passengers on routes that could not economically support locomotive-hauled dedicated passenger trains and thus had to settle for undesirably slow mixed trains (freight trains with passenger carriages attached).World War I and its subsequent economic impacts brought research to a halt after three unsuccessful experiments.