+---------------------------------------+
| | ft. in. |
+-----------------------+---------------+
|Total length of engine.| 32 8 |
+-----------------------+---------------+
|Width between frames. | 4 1 |
+-----------------------+---------------+
|Wheel base, total. | 16 9 |
+-----------------------+---------------+
|Diameter of cylinder. | 1 6½ |
+-----------------------+---------------+
|Length of stroke. | 2 3½ |
+-----------------------+---------------+
|Grate surface. | 25 sq. feet. |
+-----------------------+---------------+
|Total heating surface. | 1,400 sq. ft. |
+-----------------------+---------------+
|Weight empty. | 38 tons. |
+-----------------------+---------------+
|Weight full. | 42 tons. |
+---------------------------------------+
The high speeds--77 to 80 miles an hour--in view of which this stock
has been constructed have, it will be seen, caused the elements
relative to the capacity of the boiler and the heating surfaces to be
developed as much as possible. It is in this, in fact, that one of the
great difficulties of the problem lies, the practical limit of
stability being fixed by the diameter of the driving wheels. Speed can
only be obtained by an expenditure of steam which soon becomes such as
rapidly to exhaust the engine unless the heating surface is very
large.
The tender, also fitted with wheels of 8 ft. 3 in. in diameter, offers
no particular feature; it is simply arranged so as to carry the
greatest quantity of coal and water.
M. Estrade has also designed carriages. One has been constructed by
MM. Reynaud, Bechade, Gire & Co., which has very few points in common
with those in general use. Independently of the division of the
compartments into two stories, wheels 8 ft. 3 in. in diameter are
employed, and the double system of suspension adopted. Two axles, 16
ft. apart, support, by means of plate springs, an iron framing running
from end to end over the whole length, its extremities being curved
toward the ground. Each frame carries in its turn three other plate
springs, to which the body is suspended by means of iron tie-rods
serving to support it. This is then a double suspension, which at once
appears to be very superior to the systems adopted up to the present
time. The great diameter of the wheels has necessitated the division
into two stories. The lower story is formed of three equal parts,
lengthened toward the axles by narrow compartments, which can be
utilized for luggage or converted into lavatories, etc. Above is one
single compartment with a central passage, which is reached by
staircases at the end. All the vehicles of the same train are to be
united at this level by jointed platforms furnished with hand rails.
It is sufficient to point out the general disposition, without
entering into details which do not affect the system, and which must
vary for the different classes and according to the requirements of
the service.
[Illustration: M. ESTRADE'S HIGH SPEED LOCOMOTIVE.]
M. Nansouty draws a comparison between the diameters of the driving
wheels and cylinders of the principal locomotives now in use and those
of the Estrade engine as set forth in the following table. We only
give the figures for coupled engines: