1922.] Jenkinson.—Development of the Locomotive. 
291 
THE FUTURE DEVELOPMENT OF THE LOCOMOTIVE 
IN NEW ZEALAND.* 
By S. H. Jenkinson. 
Locomotive design and development is at present at a very interesting 
stage in New Zealand, because the maximum fuel-efficiency possible under 
the existing limitations and methods of operating appears to have been 
reached in the latest design. By this I do not mean to infer that no 
further progress in the economy of locomotive operation can be made, 
but to record my considered conviction that further progress depends upon 
factors not under the control of the locomotive-designer per se, as, for instance, 
the improvement and strengthening of the permanent-way, the strengthening 
of the under-frames and draw-gear of the rolling-stock, or the discovery of 
some new method of using coal or steam for the generation of power. 
Putting the same ideas in other words, I would say that the only possible 
sources of improved economy are an increase in the size, weight, and power 
of the locomotives, which are now made as large as the present bridges and 
rolling-stock will allow, or a new principle for avoiding the heat-degradation 
inseparable from the present form of steam-engine. That being so, it is 
possible to state the case confidently for the steam-locomotive and to weigh 
the claims of any suggested changes without any mental reservations as to 
the probability of material improvement in the working of the existing 
types. 
It must, of course, be thoroughly understood that, as is inevitably the 
case in any large operating concern, the average practice lags far behind 
the highest, and any comparisons based upon average or minimum loco¬ 
motive performance are quite misleading. There is, however, one uncertain 
element in all current calculations, and that is the present unsettled 
market for money and labour. This is really less disturbing to com¬ 
parisons than most people suppose, since the rate of interest and the 
scale of wages bear a more constant proportion to one another than is 
usually imagined. The net result upon comparisons of a period of high 
prices is to favour unduly the outlay of money upon capital expenditure 
rather than upon recurring labour and working charges, but the influence 
is quite small, and as it acts against the steam-locomotive in any com¬ 
parisons I may make I will content myself with pointing out the tendency. 
Before dealing with the specific problem a clearing of our ideas upon 
the vexed question of gauge is advisable, and, adopting the Euclidean 
method of stating the conclusion first, I say that the 3 ft. 6 in. gauge, the one 
laid in New Zealand, is probably slightly better than any other for any 
class of line whatsoever, but that no gauge has sufficient advantage over 
any other usual gauge to justify a break of gauge in any one country or 
railway system. The first item to consider is the cost of the permanent¬ 
way. This varies very little indeed with the distance between the rails. 
Buildings, tunnels, rails, spikes, signals, track-laying, and right-of-way or 
land are not affected by the track-gauge, and bridges are, if anything, 
* A paper read before the Technological Section of the Wellington Philosophical 
Society, 20th July, 1921. 
