but somewhat narrower. The work was also extended westward from the
First Avenue shafts to include the excavation of top headings in each
tunnel for a distance of 100 ft. and an enlargement to full size for 50
ft. The borings having shown that soft earth existed below the grade of
the tops of the tunnel under the passenger station building of the Long
Island Railroad on the east side of Front Street, and that earth of
varying character would be met in places beyond the station building
under the railroad tracks in the passenger yard and the street car
tracks in Borden Avenue, it had been decided, before proposals were
invited, to extend the metal lining eastward to East Avenue, at the east
end of the work embraced in the original contract, where the rising
tunnel grades approached the surface of the ground so closely that their
further extension would be in open cut. In places where the tunnels were
wholly in rock, the weight of the cast-iron tunnel lining was reduced
43%; where the surface of the rock was below the top of the tunnel, but
above the axis, the reduction of weight was somewhat less, about 25%;
notwithstanding these savings, the cost of the tunnels was probably
increased by the use of the cast-iron lining; on the other hand, when
passing through bad ground, a section of tunnel could be made absolutely
safe more quickly by erecting the lining as soon as a length of a few
feet of tunnel was ready; under a crowded passenger yard, this feature
had great value.

The execution of the work under this contract will be described fully by
the Resident Engineers.

The plant assembled by the contractors is believed to be the most
extensive ever placed on a single piece of work, and will be described
in detail by their Managing Engineer, Henry Japp, M. Am. Soc. C. E.