The N.Z. Journal of Science and Technology. 
325 
1918.1 
haulage is, if anything, cheaper per locomotive-mile or per ton-mile. 
The main point is not that there is a difference of a few decimals one way 
or another, but that a greater train-movement is possible, and the capacity 
for traffic is increased at a comparatively small capital expenditure com¬ 
pared with the alternative of regrading or duplicating the line. 
A few examples will now be quoted with the object of strengthening 
and reinforcing the opinions expressed in the foregoing paragraphs. 
Examples of Electrification on Grades. 
A notable example of the limitations imposed by grades is the Genoa- 
Giovi line on the Italian State railway connecting the port of Genoa 
with the valley of the Po. The length of the line in question is 14'4 miles, 
and is a mountain division formed by a spur of the Apennines separating 
the harbour of Genoa from the valley of the River Po. This line has a 
Tuling grade of 3-5 per cent., and six tunnels, of which the longest is the 
Giovi Tunnel, 2-02 miles long, with 2-9 and 3-0 per cent, grades. The 
line is double, yet owing to the increase in traffic a parallel line was built 
in 1889, 13-7 miles long, double track, with easier grades, not exceeding 
1-6 per cent., and limited to 1T6 per cent, in the longest tunnel, which 
is 5-15 miles long. These two lines are paralleled by still another line, 
the Genoa-Asti line, and there are other indirect lines, but in spite of 
this the traffic reached the limit of the transportation facilities in 1906, 
resulting in a congestion at the Genoa docks. In 1907 a new and special 
type of locomotive was built which improved the conditions considerably; 
but the increase in traffic soon overtook the capacity of the new locomotive, 
and in consequence the construction of another line was contemplated, 
and plans and estimates prepared for a double line with easy grades, but 
entailing a long tunnel, 11-8 miles long, the cost of which was estimated 
at £6,000,000. As an alternative the Genoa-Giovi line was electrified and 
put in service in 1911, the broad result being that whilst under steam- 
service conditions the average was 24 up trains and 21*3 down trains per 
day of twenty hours, the immediate result of electrification was an increase 
to an average of 33 up trains and 22 down trains in seventeen hours, 
whilst it was possible also to increase the trailing-load. It is estimated 
by the railway authorities that the capacity of the line has been increased 
threefold. This, however, is not entirely due to increased speed possible 
with electric locomotives, but to the fact that the tunnel on the 2-9 to 
3 per cent, grade, 2-02 miles long, caused such delays under steam 
-conditions that the capacity of the line was limited by this feature. The 
electrification of the line has enabled the passage through the tunnel to 
be accelerated and the block system to be operated so as to enable a 
fifteen-minute or even ten-minute headway to be obtained, and on this 
basis, taking into account the increased speed, the increased headway, 
and the bigger trailing-loads, the railway authorities estimate that the 
capacity has been increased, as stated, twofold for fifteen-minutes headway, 
and threefold for a ten-minutes headway, working twenty hours per day. 
Another notable example of an electrification of a railway in which 
the grades under steam conditions had become a limiting feature is the 
■Butte and Anaconda line, which is a heavy mineral line, the total length 
of single track consisting of about thirty-eight miles of main line and fifty- 
three miles of yards and sidings, making ninety-one miles in all. The 
ruling gradient is 3 per cent., and on the grade the speed of a 53-car freight- 
train with a load of 4,000 tons was limited under steam-service conditions to 
7 miles per hour. The average speed on the west trip, which is against grade, 
