We illustrate a very remarkable locomotive, which has been constructed
from the designs of M. Estrade, a French engineer. This engine was
exhibited last year in Paris. Although the engine was built, M.
Estrade could not persuade any railway company to try it for him, and
finally he applied to the French government, who have at last
sanctioned the carrying out of experiments with it on one of the state
railway lines. The engine is in all respects so opposed to English
ideas that we have hitherto said nothing about it. As, however, it is
going to be tried, an importance is given to it which it did not
possess before; and, as a mechanical curiosity, we think it is worth
the consideration of our readers.
In order that we may do M. Estrade no injustice, we reproduce here in
a condensed form, and in English, the arguments in its favor contained
in a paper written by M. Max de Nansouty, C.E., who brought M.
Estrade's views before the French Institution of Civil Engineers, on
May 21, 1886. M. Nansouty's paper has been prepared with much care,
and contains a great deal of useful data quite apart from the Estrade
engine. The paper in question is entitled "_Memoire relatif au
Materiel Roulant a Grand Vitesse_," D.M. Estrade.
About thirty years ago, M. Estrade, formerly pupil of the Polytechnic
School, invented rolling stock for high speed under especial
conditions, and capable of leading to important results, more
especially with regard to speed. Following step by step the progress
made in the construction of railway stock, the inventor, from time to
time, modified and improved his original plan, and finally, in 1884,
arrived at the conception of a system entirely new in its fundamental
principles and in its execution. A description of this system is the
object of the memoir.
The great number of types of locomotives and carriages now met with in
France, England, and the United States renders it difficult to combine
their advantages, as M. Estrade proposed to do, in a system responding
to the requirements of the constructor. His principal object, however,
has been to construct, under specially favorable conditions, a
locomotive, tender, and rolling stock adapted to each other, so as to
establish a perfect accord between these organs when in motion. It is,
in fact, a complete train, and not, as sometimes supposed, a
locomotive only, of an especial type, which has been the object he set
before him. Before entering into other considerations, we shall first
give a description of the stock proposed by M. Estrade. The idea of
the invention consists in the use of coupled wheels of large diameter
and in the adoption of a new system of double suspension.
The locomotive and tender we illustrate were constructed by MM. Boulet
& Co. The locomotive is carried on six driving wheels, 8 feet 3 inches
in diameter. The total weight of the engine is thus utilized for
adhesion. The accompanying table gives the principal dimensions: