The Twin City star. [volume] (Minneapolis, Minn.) 1910-19??, 1918-09-07
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flood period, 1t allows the river to flow
on uninterrupted. while during the
navigation season 1t serves its full
purpose as dam and may be so OPP
Grated as to pass a large or small
quantity Of water, thus keeping each
pool at its proper level.
Highest Lift Locks.
There are SO locks on the Erie
canal. all Of which are massive con-
crete structures, having inside rec
tangular dimensions of 300 by 44.44
feet and lifting capacity varying
from few feet up to 40R feet. At
waterford the locks are so constructed
that series of five serves to lift the
barges from the Hudson river to the
canalized Mohawk river, 169 feet above
the level Of the government lock at the
Troy dam. These structures have
been called the worlds greatest series
OF high-lift locks and their lift is dou-
BILE that Of the locks in the Panama
canal from sea level to summit.
One Of the highest lift locks in the
world is located at Little Falls. where
the difference In pool elevation Is 4O11a
! feet. This massive structure has con-
crete walls, which stand 80 feet high
and are 30 feet wide at the base. The
lower gate Is Of the lift type and is
raised and lowered, instead of being
| swung open and shut as are the gates
on other locks.
In the operation Of all locks the wa
ter is admitted to and drawn from the
chamber by means Of culverts rum
ming through the side walls. and the
| openings have been so designed that
the filling and emptying of the cham
Der Is only matter Of few minutes.
| The locks are all electrically op-
Grated and the chambers are filled or
einptied while the gates and valves
! are opened or closed by simply turn
ing lever. Safety devices are also
arranged s6>that errors in operation or
navigation are practically eliminated.
The Erie canal is spanned by 232
bridges, Of which so are railroad cross
ings. The clearance under these struc-
lures must be at least 15A feet.
| Guard Against Accident.
In the ''land line," guard gates have
| been provided which are located about
ten miles apart. These are steel struc-
lures, suspended from towers and may
be lowered to hold the water, in case
Of emergency, such as might exist IL an
embankment became weakened or any
similar accident made 1t desirable to
| unwater any section Of the channel.
| Numerous culverts and spillways
which keep the water from overflow
ing the banks have been provided and
a hundred million yards Of earth and
rock have been removed, while three
million yards Of concrete have been
placed.
While the actual construction period
has been about 13 years, this, consider
ing the magnitude and ramifications of
the work, is very short time. The
many structures and the nature Of the
territory through which the different
| channels ruI. has made this one Of the
really important engineering undertake
| ings Of the age, and the construction
| details have been the most extensive.
] the plans alone being some Of the most
| elaborate and complete ever drawn up
for any large construction work.
The cost of handling freight on the
railroads, before recent increases went
into effect, varied from two to seven
mills per ton per mile, the average be-
| ing between three and six mills per
| ton mile. 1t is now estimated that this
| figure will be reduced more than one
| half on the new canal system. owing to
the larger barges and the thoroughly
up-to-date facilities. The method Of
propulsion used is by power boats
driven either by steam, electricity or
the internal combustion engine, and 1t
| has already been determined from
trial trips that the speed which may be
maintained throughout the system Is
considerably In excess of that main