The times. [volume] (Richmond, Va.) 1890-1903, 1902-07-05

box there was ono danger to be avoided
the river. bottom might sink after the
water had been pumped out To obviate
a trouble of this sort piles are driven at
right angles to the line OF the tunnel, four
piles every eight feet These piles are
cut OF under tho water at the proper
distance from the surface, and then they
arc capped" and braced with diagonal
braces to make them firm under very
great pressure. The box is to rest partial
~ on the caps, SO that it cannot sink
gown, no matter what happens to the
river bottom
1t has been no simple matter to drive
the piles properly; Their tops after being
| as the grade of the tunnel, and they have
been driven SO successfully that the line
formed by the caps is true within twu
ohe-nundredthS of an inch.
After the plle-driving, the next operation
is tho insertion of ''wailings" and "brac-
| nnss 10 support the sides OF the boN
ions Of the subway under the city streets
In Fourth Avenue for ins;ance-the
.,waflings" being the transverse beams
that help to form the maze of wood
through which one looks down into the
| tunnel in passing over the line on foot
| or In a trolley car. The woodwork in the
Avenue in that it is much heavier. 1t
has to be heavier, for the strain upon
1t is far greater.
are sunk. forming a skeleton around which
the box is to be made the next stage OF
the work consists of driving the sheeting
stead of using three-inch planks for
sheetng is done in Fourth Avenue.
the river tunnel builders use twelve-inch
tinnbers.
that they represent, with their tongues
and grooves, thirty-eght inches along
the sides of the big box. The sheeting
is driven five or ten twelve feet below
the bottom line of excavation. and then
It is cut off just above the line Of the
completed tunnels roof.
SINKING BOX'S ROOF.
Following the completion of the sides
Genes the sinking of the box's roof or
top. This roof is to be forty inches thick,
made of solid timbers and held together
by longitudinal beams running along
both its top ana bottom and bolted
through. The box having been finished,
earth will DO heaped around it. making it
water-t!ght and adding another force to
hold 1t in place. Then the water on the
inside viii be pumped out, and the box
will be ready for use by the workmen
who are to lay inside it the two tubes
for underground trains.
Although Mr.. Mclean plans to use no
compressed air. his box being built with
s. view OF using It if necessary. Unless
enters the box from two openings. On
tho land side the entrance to the box will
bs beyond tho waters edge. and out in
The center o fthe river there is to be
wooden shaft protruding from tn sur
face of the water.
AS indicated above. the only chance
that compressed air will have to ne used
lies In the danger of the river bottoms
blowing II It does blow Mr.. Nc
I>,,Il-b Ia how md I'LL il
with enough compressed air to hold tho
rising soil down to its proper position.
But he does not expect any such neces-
sitv. as he calculates on finishing the
worl, in so great hurry that there Will
b.. no time for the bottom to blow
sufficiently to cause trouble
PRESENT CONDITION.
The present condition Of the river work
is as follows Inc Inc are, dTeas ars down a and
capped: the .'waiiinSs ana oiacliie9
are being sunk. -,
Within fortnight they viii ~, b pf;,aon 10
tractor says he expects to be ready 10
pump the water out OF the box III sep.
tember. Then the work VIII be ainose
the river is concerned Before next CHRIST
mas the builders are confident OF nay
ing everything ready for start on lhe
Bronx side of the stream. having com,
n)eted the work on this side and cleared
The nearest channel for traffic. No douoe
is felt that all the river stretch, meas
,Iriner / .504 feet In length. will be ready
for Service before Christmas. 1908. which
IS the date set for running the first train
In the approaches to the tubes tina,
will run under the water the lining OF
the tunnel is to consist of concrete arch
es. The tubes themselves. twelve and one,
half feet between centerS and separated
nv n diaphragm. will be covered on the
Outside with concrete and lined with cast