Durango semi-weekly herald., 1907-03-18

marked very seriously that there |
would be at least one portion Of a
on which the passengers
would not be troubled with dust. The
roadbed will be thirty-one feet above
the water the entire distance, which
is believed to be sufficient height to
resist any gale that may possible dis
turb those shallow waters. The con-
struction will be sufficient to resist
any pressure.
The work is in charge of ]. C. Mere
dith. In reviewing the work he says:
I'VE began work May 1, 1905, and
are about one-third done. Out of
total of 126 miles along the keys we
have seventy-one miles graded and
either laid with iron or ready for it.
The concrete work is perhaps Is or
90 per cent completed, and we are
building at the rate of fifty feet, or
one span, per day. The concrete work
and some other problems which we
thought would be difficult have turn
NO, we are not the first to adopt
concrete in railroad construction. Sew
eral roads in the United States have
used 1t a good deal. The st. Paul
road was the first to take 1t up for
culverts, and soon found it to be prac-
ticable for more extended work. The
Big Four road is taking out steel and
placing IL with concrete. The Chi
cago. Burlington and Quincy, the IL
linois Central and other roads are u.s.
ing 1t more or less extensively We
have not had the slightest trouble.
We are building four concrete via
ducts, REINFORCED with steel, with
fifty-foot spans resting on piers set
into the solid rock and strengthened
with piles. The base of the pier at
rock surface is twenty-eight feet and
at the springipg line of the arch 20
feet Z inches. From the water to the
crown of the arch will be twenty-five
feet at mean low tide. To this should
be added the thickness of the arch
at the crown, the ballast and the ties,
which make the track thirty-one feet
above the level of the water. There
will be three drawbridges with open
ings aggregating 40 feet.
THE longest viaduct is 1O,5OO feet
from Long Key to Conch Key, the
second is 1900 feet across knights
Key channel, third of 1890 feet
across Missouri Key channel and a
fourth of 1850 feet across Bahai Hon
da Key channel, making a total of 3d.
$50 feet of concrete, equivalent to 5.7S
miles.
In building the concrete work we
first drive pine piling for a founda-
tion from four to ten feet into the
coraline rock at the bottom, which is
usually soft enough. Where it is not
soft enough we use steel punch with
9.300-pound hammer. These keyes
and the bottom of the water between
them are not always composed of the
traditional coral in places 1T has de-
cayed and dislntegrated and has silt
ed and formed into a soft limestone
that will stand pressure of 1850
pounds to the inch. Having driven
| our piles, We put Golfer dam over
the site of the pier. pump out the wa
ter. clean the bottom of mud and
lay floor of concrete three feet thick.
We allow that to set for four days:
then we cut off the piling at the level,
erect wooden form for the pier an
! chor the steel framework and place
the concrete in position In blocks of
the size of one cubic yard We fill
up the pier form to the arch line,
erect the arch-centering and spandril
walls, and, finally, raise the concrete
to the proper height. We use Alsen
cement. that company being the only
one that could comply with our speci-
flcations, which require unusual fine
ness and purity in grinding to insure
permanence.
After leaving the mainland at
Homestead" continued Mr. Meredith,
I'VE had to pass through twenty miles
of Everglades. many feet deep of muck
and mari. and very soupy. Our en-
gineers would sink up to their arm
pits in the mud. We put In six side
barrow dredges and dug out bitches
on either side, using the earth to make
an embankment in the middle. We
anticipated that the embankment
would take year to harden, but after
two months. we found that we had a
solid and substantial track. After that
twenty miles was finished we struck
tidewater, crossed to Key Larke, the
largest of the keys, and put in our
first concrete work, which turned out
all right Last winter we graded ev-
cry key on our line that was high
enough to allow us to work. We kept
1000 men busy all winter. We have
finished the grading on nearly every
key, and in a few months will have
completed all the work that can be
done by hand. 1t was quite a prob
lem to take care of the men on the