well rammed about the blocks and rounded off 6 in. above the surface of the ground.  Secure flashings, in two sections, were then made about the posts to cover the holes made in the gutter and roof, the bottom sections being firmly soldered to the roof or gutter, and the top sections, which lapped over the bottom and cleared them 2 in. in all directions, were firmly nailed to the posts and the joints leaded.  This arrangement allowed the bents to move slightly, and at the same time made the roof and gutter water-tight.  These bents were placed 16 ft. on centers to correspond with the spacing of the doors of the freight shed.

Under the cross-overs near Eleventh Avenue, where the tracks had to be supported in different positions on the caps, and could no longer be kept over the posts, the caps were trussed and the posts were reinforced, as shown on Bents “J,” “H,” and “K,” Fig. 5.

  [Illustration: 
  Fig. 5. 
  DETAIL OF BENTS FOR MATERIAL TRESTLE]

The trusses for the through bridge over the tracks were erected on Sunday, April 16th.  The two trusses, one 122 ft. and the other 165 ft. 8 in. from center to center of end posts, had been assembled and riveted, lying flat on cribwork a few feet above the ground, south of the permanent position and between the New York Central tracks and Eleventh Avenue.  On the date stated, the contractor, having been given permission to block the Central’s tracks from 5 a.m. to 9 p.m., erected a large steel gin pole just south of the correct position of the center of the north truss, which was then dragged, from the place where it had been assembled, across the railroad tracks until the center of the bottom chord was vertically under its true position, the truss still lying flat and about at right angles to the center line of the bridge.  Chains were made fast to the top chord at the middle panel of the truss, which was then turned up to a vertical plane, raised to its permanent position, and guyed.  The gin pole was then shifted and the operation repeated with the longer truss, after which, half of the floor beams and a part of the top laterals were bolted in position and the guys were removed, the bridge being thus erected without the use of falsework of any kind.  During the lifting there was no sag in either truss that could be noticed by the eye.  Fig. 1, Plate LV, shows the bridge erected, with the exception of the tight timber fence.

Pier No. 72 is directly over the North River Tunnels.  When it was turned over by the New York Central Railroad Company, the contractor for the construction of those tunnels tore down the shed and removed the deck and such piles as were in the path of the tubes.  This left standing the four northernmost, the four southernmost and two centers rows of piles for the entire length of the pier.  An additional row of piles was then driven on either side of the two center rows, and battered so that at the elevation of the tunnels they would be close to the center rows and leave as much clear space as possible.  The pier, therefore, was constructed of three independent lines of four-post bents, which, however, rested on sills which were continuous throughout the width of the pier, as shown by Figs. 2 and 3, Plate LV.