324 The N.Z. Journal of Science and Technology. [Nov,. 
bridges, increasing the number of passing-places, and so on—and the 
traffic continues to increase, then the railway management will be faced 
with the necessity of extensive regrading and deviating, and later on with 
duplicating, the line. If at this juncture an adequate supply of electric 
power were available the same result would follow as in other similar- 
cases—viz., the Railway Department would adopt the most economical 
solution of the problem and electrify the section or division in question.. 
It is important to notice this : that on the assumption that the capa¬ 
city for traffic over this section is doubled as the result of electrification— 
a result which has been exceeded in other cases—the capacity of the whole 
through system is thereby doubled at the expense of the cost of electrifying 
only a comparatively short length ; and, further, it would have the effect 
of enhancing the value of the whole of the North Island railway system,, 
as the effect of a construction in any one part—especially a part so vitally 
situated as the section in question—affects the whole railway system. It 
will be seen that it is not at all necessary to go to the expense of electrifying 
the whole system in order to improve transport facilities, but that all that 
is necessary is to electrify certain critical sections when and as the limits of 
steam haulage are reached, leaving the remainder of the system to be 
worked by the more economical steam haulage. And as under conditions 
of easy grades steam haulage is capable of a very large expansion, a very 
long time would elapse before the traffic would increase to such an extent 
as to justify the expense of electrification throughout. Thus electrification 
would proceed by easy stages- now a small step, now a large one—but 
each made only when the necessity for it arose and when economically 
justifiable. Now, in order to render such an orderly development possible 
a comprehensive system of electric-power distribution from which a supply 
of power can be obtained when and as required is a sine qua non. 
Cost of Electrification. 
A word as to the cost of electrification and the relative cost of operation.. 
It may be taken that in New Zealand the cost of equipping a single line,, 
including distribution lines, substations, overhead contact lines and feeders, 
track-bonding and track-feeders, and allowing also for repair plant, work- 
shop tools, and housing of staff, and the lighting of stations and yards, but 
not including locomotives, would not be far short of £5,000 per mile— 
always on the assumption that a supply of power is obtained at con¬ 
venient points from a power-supply system, thus eliminating any expendi¬ 
ture upon power-houses or upon transmission from the source to the points 
of distribution. This is not a large expenditure when considered in its 
relation to the cost of construction of railway-lines over mountain sections, 
involving as they do tunnels, deep cuttings, high embankments, and bridges ; 
and it is upon a section of this description that electricity is used to 
the greatest advantage. Further, when it is considered that electrification 
increases the capacity of the line for traffic possibly 100 per cent, or more 
in some cases, not only over the section electrified, but over the remainder 
of the railway system dependent on the section, it will be seen to afford a 
very inexpensive way of securing the benefits of a duplicate line without 
the cost of duplication. 
Now, as regards the cost of operation, let no one assume that it is 
cheaper to operate an electric service than a steam service where the con¬ 
ditions are within the limits of economical haulage by steam : such is not 
the case. Where, however, the conditions are such as to approach to 
the limits of steam haulage— e.g., on a mountain section—then electric- ‘ 
