Elevated railways have been in operation for a long time in New York,
Berlin, and Vienna, and the city of Paris has decided to have recourse
to this mode of carriage, so indispensable to large cities. The
question of establishing a line of railways in our capital has been
open, as well known, since 1871. During this period of nearly fourteen
years this grave subject has at various times given rise to serious
discussions, in which the most competent engineers have taken part,
and numerous projects relating to the solution that it calls for have
been put forth.
The problem to be solved is of the most complex nature, and the
engineers who have studied it have not been able to come to an
agreement except as regards a small number of points. It may even be
said that unanimity exists upon but a single point, and that is that
the means of locomotion in Paris do not answer the requirements of
the public, and that there is an urgent necessity for new ones. The
capital question, that of knowing whether the railway to be built
shall be beneath or above ground, is not yet settled; for, up to the
present, no project has been prescribed in one direction or the other.
While some extol the underground solution as being the only one
that, without interfering with circulation in the streets, permits
of establishing a double-track railway capable of giving passage
to ordinary rolling stock and of connecting directly with the large
lines, others, objecting that such a road could not give satisfaction
to the taste of Parisians, and that it would necessitate work out of
proportion to the advantages gained, conclude upon the adoption of an
open air railway.
Preferences generally are evidently for this latter solution.
We have received from a learned engineer, Mr. Jules Garnier, a
project for an elevated railway, which appears to us to be very ably
conceived, very well studied out, and which we hasten to make known.
(1.) The system is characterized by the following fundamental points:
The up and down tracks, instead of being laid alongside of each other,
as in an ordinary railway, are superposed upon two distinct platforms
forming a viaduct, which is consequently so arranged as to permit of
the laying of one of the tracks at its lower part and of the other at
its upper.
(2.) The system of constructing the viaduct is so combined as to be
capable of giving passage upon the road to the rolling stock of the
large lines during the stoppage of the daily passenger trains.
(3.) The tracks are connected at the extremities by a curve that has
the proper incline to compensate for the difference in level between
the two, and which has a sufficiently large radius to allow the slope
of the track to be kept within the limits admitted. The running of the
trains is thus uninterrupted.
(4.) When two lines of different directions bisect one another, a
special arrangement permits the passengers from one line to pass to
the other by means of what is called a "tangent" station, without
the trains of one line crossing the tracks of another, the purpose of
which arrangement is to avoid those accidents that would inevitably
occur through the crossing of a track by the trains of a transverse
line.
(5.) The rolling stock is arranged in a manner that allows the
entrance and exit of the passengers to be effected with great
promptness.
In ordinary avenues, comprising a roadway and two sidewalks, the
elevated railway is placed in the axis of the roadway at a sufficient
height to prevent it interfering with the passage of carriages, say
14¾ feet above the surface, while in boulevards or avenues of great
width, having _contre-allees_[1] bordered by a double row of trees, it
is installed in one of the _contre-allees_.
[Footnote 1: Paths parallel with the public walks.]
In the first case (Fig. 1), the viaduct is wholly metallic, while
in the second it comprises masonry arches surmounted by a metallic
superstructure. The viaduct is formed of independent spans supported
by metallic piers that rest upon masonry foundations (Fig. 2).
[Illustration: FIG. 1.--PROJECT FOR A PARISIAN ELEVATED RAILWAY.]
[Illustration: FIG. 2.--LONGITUDINAL ELEVATION.]
The line will have three kinds of stations, intermediate, "tangent,"
and terminal ones. It is at the latter that the two superposed lines
are connected by the circular inclined plane.
The waiting platforms of the intermediate stations will be formed
simply by the widening of the span corresponding to the station.
Access to these platforms will be had by stairs running up from the
edge of the sidewalk. The passengers will make their exit by means of
corresponding stairs on the opposite side. (Figs 3 and 4.)
[Illustration: FIG. 3.--A STATION.]
[Illustration: FIG. 4.--TRANSVERSE SECTION OF STATION.]
The tangent stations are placed at the meeting point of two lines,
which, instead of crossing each other, are bent inward like an X, the
two parts of which will be tangent to the central point. Through
such arrangements the running of the trains will be continuous, and
a traveler reaching one of these stations will be able, upon changing
train, to take at his option any one of the three other directions.
As may be seen, Mr. Garnier's project presents conditions which
are very favorable to the establishment of an elevated road in the
interior of Paris. Far from injuring the aspect of the great arteries
of our metropolis, the viaduct, as it has been conceived, will
contribute toward giving them a still more imposing look. If the
beautiful is, as has been said, the expression of the useful, an
elevated railway, well conceived, may be beautiful. The project of
a subterranean railway is attended with great drawbacks, not only
as regards the great expense that it would necessitate, but also the
difficulties of constructing it. And there is a still graver objection
to it, and that is that it would oblige travelers to move like moles
in dark, cold, and moist tunnels. At Paris, where we are accustomed
to a pleasant climate and clear atmosphere, we like plenty of air and
broad daylight.--_La Nature._
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