300 
The N.Z. Journal of Science and Technology. 
[Jan 
Table III. 
Wellington- 
Lower Hutt. 
Rimutaka. 
Steam. 
Electricity. 
Steam. 
Electricity. 
Miles of single track 
Cost of electrification 
Trains per day each way 
Locomotives required 
Cost of locomotives 
40 
7 of 70 tons 
£42,000 
18 
£81,000 
40 
6 of 70 tons 
£78,000 
10 
4 of 60 tons 
£24,000 
5 
£30,000 
10 
4 of 60 tons 
£48,000 
Repairs of locomotives per year 
Fuel of locomotives per year.. 
Electricity at f d. per unit 
Interest and depreciation 
£5,000 
£7,000 
£3,780 
£2,500 
£6,500 
£13,500 
£3,000 
£3,000 
£2,160 
£1,500 
£2 * 250 
£6,720 
Total working-expenses . . 
£15,780 
£22,500 
£8,160 
£10,470 
The advantages that are claimed by the perfervid advocates for electric 
as compared with steam locomotives dwindle down woefully when con¬ 
fronted with New Zealand conditions. Dealing with them seriatim,—- 
(1.) No greater tractive effort can be exerted with electric locomotives 
than with steam, because of the limitations of the draw-gear and under¬ 
frames of the present rolling-stock. Much stronger steam-locomotives 
would be built to-day if it were not for this reason. 
(2.) No greater horse-power can be exerted. The limit of power of the 
present steam-locomotive is seldom reached, being hindered by speed- 
restrictions due to curves and light lines, load-restrictions due to platform 
and siding length or to the presence of ruling grades combined with the 
limitations of draw-bar pull mentioned above. 
(3.) The use of regenerative braking offers no advantages, because of 
the few trains running. This would not apply, of course, to the electrifi¬ 
cation of long lengths of main lines. 
(4.) The large reduction in cost of locomotive repairs is offset by the 
repairs to the overhead line and other electrical equipment. The cost 
of these would loom large in comparison on account of the small number 
of train-miles run. 
(5.) No reduction in train-mile expenses would result, since heavier 
or faster trains could not be hauled, and in any case the number of trains 
is largely governed by time-table exigencies in studying the convenience 
of the public. 
(6.) Increased cleanliness would certainly result owing to the absence 
of smoke, but it is evident the same end could be much more cheaply 
attained by the use of powdered coal than by the adoption of electricity. 
Having disposed of the two fashionable fallacies, wider gauge and elec¬ 
trification, a few words remain to be said on the general tendency of steam- 
locomotive design. Before, however, the problem can be intelligently 
discussed it is necessary to know something of the practical efficiency of 
the locomotive, and to do this it is necessary to consider the efficiencies 
of the boiler and cylinders separately. Still utilizing the data ascertained 
in the trials already mentioned, Table IV has been prepared. 
Table IV. —Efficiency of the Locomotive-boiler. 
B.Th.U. in 1 lb. coal 
B.Th.LL given to water per 1 lb. coal (9 lb. at 650° E. to 180 lb. 
pressure and 620° F. superheated less 10 per cent, saturated) 
B.Th.U. in chimney-gases (13 lb. at 400° E.) 
Efficiency = 
12650 
14000 = 90 per cent - 
14,000 
11,550 
1,100 
