|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