The railway system of the Argentine Republic is separated from the
Chilian system by the chain of the Andes. The English contractors,
Messrs. Clark & Co., have undertaken to connect them by a line which
starts from Mendoza, the terminus of the Argentine system, and ends at
Santa Rosa in Chili, with a total length of 144 miles. The distance
from Buenos Ayres to Valparaiso will thus be reduced to 816 miles. The
Argentine lines are of 5.4 foot gauge, and those of Chili of 4.6 foot.
The line in course of construction traverses an extremely hilly
region. The starting and terminal points are at the levels of 2,338
feet (Mendoza) and 2,706 feet (Santa Rosa) above the sea; the lowest
neck of the chain is at the level of 11,287 feet.
Study having shown that a direction line without tunnels, and even
with the steepest gradients for traction by adhesion, would lead to a
considerable lengthening of the line, and would expose it to
avalanches and to obstructions by snow, there was adopted upon a
certain length a rack track of the Abt system, with gradients of 8 per
cent., and the neck is traversed by a tunnel 3 miles in length and
1,968 feet beneath the surface. The number and length of the tunnels
upon the two declivities, moreover, are considerable. They are all
provided with rack tracks. The first 80 miles, starting from Mendoza,
are exploited by adhesion, with maximum gradients of 2½ per cent. Upon
the remaining 64 miles, traction can be effected either by adhesion or
racks.
[Illustration: FIG. 1.--REGION TRAVERSED BY THE RAILWAY THROUGH THE
ANDES.]
The track is of 3.28 foot gauge, and this will necessitate
trans-shipments upon the two systems. The rails weigh 19 pounds to the
running foot in the parts where the exploitation can be effected
either through adhesion or racks, and 17 pounds in those in which
adhesion alone will be employed.
[Illustration: FIG. 2.--DIRECTION LINE OF THE RAILWAY THROUGH THE
ANDES.]
The special locomotives for use on the rack sections will weigh 45
tons in service and will haul 70 ton trains over gradients of 8
percent. Those that are to be employed upon the parts where traction
will be by adhesion will be locomotives with five pairs of wheels,
three of them coupled. The weight distributed over these latter will
be 28 tons. These engines will haul 140 ton trains over gradients of 2
per cent.
The earthwork is now finished over two-thirds of the length, and the
track has been laid for a length of 58 miles from Mendoza. It is hoped
that it will be possible to open the line to traffic as far as to the
summit tunnels in 1891, and to finish the tunnels in 1893. These
tunnels will have to be excavated through hard rock. To this effect,
it is intended to use drills actuated by electricity through dynamos
driven by waterfalls. The Ferroux system seems preferable to the
Brandt and other hydraulic systems, seeing the danger of the water
being frozen in the conduits placed outside of the tunnels.--_Le Genie
Civil_.
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