New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1905-12-03
RUSH ON SUBWAY WORK
MANY, HARD PROBLEMS.
Largest Flat Roof Tunnel IN the
World, 1t Is Said.

Work is now being pushed rapidly on every
section of the Brooklyn subway. The plans for
a change from a two track to a four track con-
struction in Fulton-st, and to six and seven
track construction in Flatbush-ave, having been
finally passed, there is no part of the work
where the activity of Crawford & McNamee,
the contractors, is not to be seen. The work
is under the direction of Chief Engineer Rice,
of the Rapid Transit Commission Mr.. Noble, the
division engineer. representing the commission,
and Fred Crawford, of the contracting firm The
Rapid Transit Commission hopes that trains will
be running to the Flatbush-ave. station Of the
Long Island Railroad from the City Hall in
Manhattan in another year and a half.
Although there have been many difficult en-
cheering problems met and conquered along the
entire route, perhaps the most interesting is to
be found in what is known the Borough Hall
section, which is to extend from the end of the
river tunnel, which ends in Joraler1on-st.. just
west of Chnton-st.. to Fulton-st, just east OF
the Borough Hail. From the latter point to the
tunnel there three different kinds of con-
struCtion. In order to provide for the cross
Just before reaching the Borough Hall
station 1t was necessary to have two track
construction, which means that the two tracks
are under one roof. AS Joralemon-st. is so mar
row It was impossible to build arched roof,
and as the work is so far below the level of the
street it was not feasible to put in girder con-
struction. It was then necessary to build what
is known as fiat roof" "fat arch" tunnel.
Mr.. Crawford believes that this is the largest
flat roof tunnel in the world. It has span
of twenty-eight feet from wall to wall. This
concrete roof is from twelve to fifteen feet below
the street level, and the question came up for
solution as to whether the material for this
roof should be mixed in the bottom of the tunnel
and lifted up, which would be extremely diff
c,,It or should be mixed in the street and poured
into the moulds from above. This latter plan
was accepted. OF course, the work is so deep
that it is not open cut as in Fulton-st. but
Sc a regular tunnel The rnoulds for the con-
crete were built in sections ten feet in length and
a shaft was sunk from the street to each one.
Then the concrete was poured in from above and
allowed to harden. Some idea of the load this
roof has to hold may be gained from the fact
that there is weight Of forty tons on each
lineal foot To bear this immense strain the
roof is made four and one-half feet in thickness.
At Court and Joraiemon SITS. this flat roof"
construction passes only thirteen feet below a
point twelve feet from the foundations OF the
Temple Bar, a twelve story office building. Be
yvond this construction there 80 feet OF what
is known as single track construction, which
means that there is a supporting wall running
between the two tracks that takes up much
of the load overhead. The walls and roof here
are also concrete. Under point near the Packer
Institute begin two brick tubes, each Of which
connects with tube coming UP from under the
rivar and which is being pushed over toward the
BATTERY, These tubes, composing the river tun-
mel are being constructed by another contracting
company. From the Brooklyn shore the tubes
bora been pushed out into the river for about
five hundred feet.
SPREAD FOR THE EMPLOYEES
The south tube of the Crawford & McNamee
wori, was pushed through into the tube coming
from the rive< last Monday, marking a point IN
+he work which the contractors celebrated by
serving a stspread" to their 500 employees. 1t
was served in the tunnel itself, near Court-st-
The south tube, which has brick walls sixteen
inches thick will be entirely constructed TO the
junction with the river tube in about hfteen
davs The north tube will not be entirely I'M
isbed until some time in the winter. The tubes
Of the river tunnel running from Clinton-st.. are
built of cast steel plates, overlapping ana Do4Ceu
together Although there was considerable dam
age done to the Buildings along the line OF this
river tube no damage to speak Of has been oohe
nv the work of Crawford & McNamee' IN spite
or the fact that they have gone near the fouhua-
tons of many large buildings. me down eiauo'
which begins Just west OF the Temple Bar drops
+ubes In some places the tunnel Is htty rect
below the level of the street
According to the plans of the Rapid transit
Commission the work on what is known as lhe
RroolLvn extension is in three d1vlslons-thas
from, the City Hall to the Battery, Mammalian
that from the Battery and under the river 10
Joralemon and Clinton SITS, Brooklyn, and from
there to the Long Island station at Flatousn ana
Atlantic-aves Crawford & McNamee have the
contract for all of the latter division For their
own convenience they subdivided it into three
sections-the Flatbush section. from the staCoh
n FTatbush-ave. and Fulton-st.; the De kalo
section. from that point down Fulton-st. to a
point near Smith-st.. and the Borough Han sec
ton. from the latter point to the river tunnel
The first work was done by sinking a smart at
Fatbush-aye. and Schermerhorn-st- in April,
1904. From there the work was carried on IN IN
both directions being stopped at si-sctio ~,
March of this year, and in the other dlrecIioH
being carried down far as Fulton-st ms
U-as ali done before 1t was decided to increase
the number of tracks so as 70 accoIhIn3di5dle
express service. For many months W.lIle $50 o-s
SPF--~ rTraa in contamination the contractors