The New Zealand Railways Magazine, Volume 1, Issue 2 (June, 1926)
One of the most difficult problems to be dealt with is that of working branch lines. These are losing heavily in both Islands, but chiefly in the South, owing to the large number of such lines in that part of the Dominion. These lines were built to develop the country before the advent of good public roads and have in many cases served a good purpose. The provision of good roads and the use of motor vehicles in opposition to the railways has made quite hopeless the proposition of paying the expenditure involved and interest on construction of the lines.
Various methods are being tried to increase the revenue and decrease the expenditure on the branches. Rail motors which are proving successful in other countries are now being given a trial. What is required is a self-contained vehicle that will be more economical of fuel than the ordinary train engine and that can be worked with less than the usual crew of three men.
Reports from other parts of the world do not indicate that the want has been filled by rail motors with entire satisfaction; but the need is not peculiar to New Zealand, and there is no doubt that some development will be found to suit the need. For the sake of economy in working the passenger and goods traffic on branch lines where the volume of traffic is insufficient to warrant the running of steam trains a one man unit capable of hauling a few trucks or a couple of cars at a reasonably fast rate of speed seems to be the kind of power unit most likely to give satisfactory results.