xX. W. H. WARREN. 
consist of an extension of the elevated railroad, and the construc- 
tion of a large bridge having two fixed and one draw span over 
the Harlem River at New York. The: draw span is 389’ long, 
measured between the centres of the end connections, and is 
formed with three main trusses arranged to carry four railway 
tracks, the depth of these trusses is 64’ over the central pier, 
about which they revolve; the opening and closing of the bridge 
being operated by steam power. The side trusses are designed 
for a dead load of 2,340 ibs. per lineal foot, and the centre truss 
for a load of 4,520 Ibs. per lineal foot. The live load provided for 
is 3,000 ibs. per lineal foot per track, with an engine excess of 
8,000 Ibs. per foot on forty feet. The arrangements for distributing 
the load over the circular steel drum, which is supported on @ 
double ring of live rollers, is worthy of notice, and is effected by 
means of a a — of distributing girders. The fender 
for protecting the p is constructed of timber and thoroughly 
cross-braced, the space ites being filled with loose stone, it is 
503’ long and 63’ wide. The two fixed spans present the usual 
characteristic features of American practice in trusses. 
The elevated railroad forming the approaches to this bridge 
consists of spans of 65’ 24” and are formed with three plate web 
girders 7’ 2” deep, carrying four tracks. There is a continuous 
floor over these bridges and approaches, formed with steel trough 
ing 18” deep built of steel plates and angles 3,” thick. The plate 
web girders on the sides have a top and bottom flange section in 
the centre consisting of two plates 20” x 3” and angles 8” x 6” x fi) 
in the central girders there are three flange plates 24” x {” with 
similar angles. The web plates are 3” and 4%,” thick at the ends : 
respectively. The web is united to the flanges by a double row of 
rivets through the angles, and the stiffeners and splice joints, are 
made with a much larger rivet area than is usual in British 
practice. The steel columns which support the ends of the plate 
_ web girders, are built up of angles and plates arranged with 4 
: — somes and stand on broad bases. 
