Iowa County democrat. [volume] (Mineral Point, Wis.) 1877-1938, 1885-10-09
The Tehuantepee Ship Railway.
Daily Graphic.

The plans of the ship railway.
which we fully illustrate to day, are
the result of the studies of its project
or, Mr.. James B. Eads, since 1879.
His practical experience has particul-
arly fitted him for his great work
During the war he designed and
built fourteen ironclad war vessels,
which compelled him to master thor
oughly the science of ship building.
His later experience in the use of iron
and steel in the long span arches of
the great Railway bridge at st. Louis
gave him familiarity and experience
with the strains to which materials
are subjected under varying condi-
tions. The foundation OF the bridge,
his work on the Mississippi River in
the wrecking business, and in build
ing the jetties at the mouth of the
river, gave him an intimate knowl-
edge of river and harbor hydraulics.
His life as an engineer seems to have
been fitted by Providence by those
various experiences to successfully ex
ecute the greatest work of mis- life.
We now come to the details of the
ship railway itself. This ship Is eie>
waited from the sea level to that of the
railway by imsans of a large floating
dock or pontoon, which may be de-
scribed as huge iron box. 1t is ar
ranged to float or sink In basin, in
which its vertical movement is guided.
On each side of the basin there will be
twenty or thirty ron rods arranged
vertically and secured in the bottom
of the basin. These rods will be
capable of holding the pontoon SO
as to prevent its rising above the level
of the railway when the ship and
cradle have been taken off it. The
deck Of the pontoon is laid with rails
which will correspond exactly with
those on the land line when the pom
toon is fIoated. When in thls position
cradle on wheels and capable of
carrying the ship is run ON to the pom
toon, which Is then submerged by ad-
mitling water into it through the
slulce gates, which are regulated from
the top of two quadrangular water
tight towers attached to the deck OF
the pontoon, and between which there
is sufficient width for the cradle and
the ship to pass When the pontoon
has been submerged TO a sufficient
depth for the bottom of the ship TO
clear the supports upon which it is n
| tended she shall rest, the vessel is
| foated in from an adjacent basin and
| secured over the top of the carriage or
travelling cradle. The pontoon is then
pumped out by means of a powerful
pump, and its deck rises up to great
height above the water, its further
progress being stopped By the heads
of the vertical rods before alluded to.
The rails on the deck of The pontoon
now range precisely with those on the
land, and while the pontoon is in this
| position locomotives are backed up
and attached to the travelling cradle,
and it is started on its journey across
| the isthmus. On reaching the end OF
the line the travelling cradle is run on
another pontoon, which is sa aomerged,
and the ship foatcd off into another
] basin on its way to its destin alton. II
will be seen that the principle OF rails
| ing and lowering the ship Is broadly y
| that adopted in the Victoria Docks,
London, and elsewhere, subject, how
ever, to certain important modltica>
tions.
In order TO make the ship railway
practicable it is absolutely necessary
that the weight of the ship should be
! evenly distributed over the wheels oil
the cradle, so as to limit the weight
| upon each wheel to that ordinarily
imposed upon the driving wneels oi
| locomotives of the present day. This
| is effected by placing in the deck Of
| the pontoon, throughout its length
and breadth, a number Of hydraulic
rams. One line Of these rams extends
through the centre of the pontoon
| longitudinally, and these are design
ed to support the keel at points Six
feet and nine inches apartsthroughout
It's whole length. On each side OF
this center line there is arranged an
ether shorter line of hydraulic rams,
which are intended 10 support the
ship. On the outside Of these lines
are two other still shor1er lines for
| supporting the bottom nearer TO the
bilges, while two other shorter lines
| outside Of these again support the
| bilges and sides of the vessel. There
are, therefore, across the middle por
| ton of the pontoon no fe wsr than sew
/ en- lines of rams, while little nearer
| to the bow and stern there are but five
lines. Still nearer to the bow and
stern there are but three lines. and
finally the central lines supporting
the keel extend forward and aft OF
these side lines nearly the entire
length of the deck. These rams are
all connected together by a common
system of pipes fitted with valves By
means of which they may be saperat-
ed into certain groups. When the
pontoon is sunk and the weight Of the
| ship is on these rams, If the entire
system is connected together. it is cvi-
dent that IL there be more pressure on
one ram than on another this press>
ure will be equal throughout the
| whole system. Mr.. Eads idea is that
the ship viii not be curved in the dir
| rection Of the ships length unless the
roadway gives way under her. A
first class roadway is therefore indis-
neneahle and this having been prOs