The winch upon which is exerted the stress that
is to effect the lifting or the descent of the bridge is fixed upon the
shaft of the pinion of the said gearing, which is also provided with a
flywheel, c. The longitudinal shafts are connected by a transverse one.
e, which renders the two motions interdependent. This transverse shaft
is provided with collars, against which bear stiff rods that give it the
aspect of an elongated spindle, and that permit it to resist twisting
stresses.
The windlasses that lift the bridge are actuated by manual power. Two
men (or even one) suffice to do the maneuvering.
This entire collection of pulleys and mechanism is established upon two
brick foot bridges between which the bridge moves. These arched bridges
offer no obstruction to navigation. Moreover, they always allow free
passage to foot passengers, whatever be the position of the bridge. They
are provided with four vertical apertures to the right of the suspension
chains, in order to allow of the passage of the latter. The girders that
support the pulleys rest at one extremity upon the upper part of the
bridges, and at the other upon solid brick pillars with stone caps.
Finally, in order to render the descent of the bridge easier, there are
added to it two water tanks that are filled from the station reservoir
when the bridge is in its upper position, and that empty themselves
automatically as soon as it reaches the level of the railroad tracks.
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