The sun. [volume] (New York [N.Y.]) 1833-1916, 1906-05-19

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tthewaiy With tha work n the hoiilnes
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The. hut The most literal estimate sesrfrs to
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According to the rapld transit enslneerp
what haa bappened Ia inst this. iu pushing
tho two great shiehis forward through tho
soft sand from tis Brooklyn end on w..
sufficient air pressure was maintained,
making more pressure on tho top of the
shield thar was calculated on. This gave
tho shields a downward pitch and thcy
did not follow tho grade laid out by the
engineers, This was noticed. bit tho
shield had to he got back again TO tho
theoretical grade gradually, 80 hat II made
q bump.
Besides the deviation from the true grade
there wa another result. AZ illustrated by
the engineers yesterday IL you take a flexible
cylinder and bend ono end Of II DOWN ard
you will find that the top Of the cylinder
along toward the middle has been fattened.
That Is just what happened TO the two
tubes. They are made Of segnents Of
steel rivetted together. and whenever tho
shields took a downward pitch the top Of
the steel cylinder AVA back Of the head
ings was fattened. 1t wa this, and not
the weight Of the river bottom, that fiat
tened the tubes, the engineers say.
II the fattening had been caused by
the weight of the river bottom IL might
be cause for a great deal of alarm and
give rise to some timidity in persons ex-
pecting to travel under the river. The
whole trouble, however, has been at the
headings or where tbs new work is being
done.
As the tunnel work stands now four
ffths of it has been completed. The
plates have all been put in and lined with
concrete and it is ready for the laying
of tracks. There has not been one bit of
distortion in this completed part since
the plates were put in, showing that it
will be absolutely safe, the engineers FAY.
According to Mr.. Jacobs and othsr ex-
perts every tunnel is bound to fatten a
little. 1t is also impossible, say some OF
the engineers, 10 drive a tunnel perfectly
regular and perfectly true to the theoretical
grade in soft material. 1t is soft sand
under the river until about the middle Is
reached.
II appeared from the statements OF tbs
Rapid Transit engineers as If the entire
trouble had been due to the clhtraotors,
but it Is understood that the Rapid Transit
Construction Company, which took the
entire Brooklyn contract, is going to con-
test the matter. 1t contends that the
trc uble was duo to the original plans.
These plans were drawn by William Bar
CLAW Parsons. MI. Parsons is now a con
cutting engineer for the Belmont company.
He refused to be interviewed yesterday.
just in what way the plans were held to
be defective no one for the Rapid Transit
Construction Company would say yesterday.
On account of the bunRling work done
the city has already held back over SlOO, 900
from the Rapid Transit Construction Com
pany. This sum, In turn, 1t Is safd, has
been held back from the sub-contractor
The total distance that will have to be
reconstructed Is 900 feet-i 900 feet in the
south tube and 900 feet in the north tube.
In the original plans an allowance was
made for O slight deviation from grade.
The trains, Of course, must run on the true
grade, The clearance provided between
the top Of a car and the roof was 8 inches,
so that II the deviation was less than four
inches reconstruction would be required
But the deviation has been more than this,
so that, in addition to being a road OF bumps,
there are places whore the roofs Of the cars
would scrape, II they did not stick alto
gether.
can follow the right grade and the cars
pass through the tunnel, the roof u be
raised In spots and in other places the
bottom must be lowered: The new plates
have been ordered for this Work, and when
they are put In the tunnel will be oval in
these spots. An oval tunnel. the engineers
cay, Is, II anything, stronger than a oylin-
drical tunnel.
IL isn't the easiest kind Of work taking
out plates in a steel tube under the river.
but the engineers say they can do It,, II the
plates have to be taken out Of the roof
the freezing process will be resorted to.
This consists of freezing the mud outside Of
thetube until 1t has the consistency Of cement
and will support the weight above 1t while
the change Is being made, This frozen mud
will be chiseled out to provide for the
larger plates.
In lowering the bottom compressed air
can be Used while the old plates are taken
out and the new ones put in. h work
of lowering the bottom has been going on
for a month at q place under Hicks and
Henry streets, whore the shield OF the north
tube took a pitch. Here, however, the
work is being done with reinforced con.
orete instead OF steel plates, as the tunnel
IA not under the river there.
Reporters who went down into the tunnel
Yesterday were unable TO see any uneven
ness, and the engineers explained that
only a leveller could show where there were
Engineer Noble, who is IN charge Of the
river section for the Rapid Transit COM
mission. said yesterday that in the worst
place the tunnel would not have to be low
cred over q foot and a half.
sThara Ia M ransom he Eaid, why the