Milford Road Railroad Overpass

Information and Findings From New Jersey's Historic Bridge Inventory

Discussion of Bridge

Summary: The 1891 9-panel Howe pony truss bridge is of riveted construction. It rests on bearing plates supported on 1917 concrete abutments with wingwalls. It has timber stringers and deck. The deck is cambered, but not the truss. Three blast plates remain. Knee braces are used at each floorbeam rather than outriggers. The floorbeams are attached to only the inside plate of the bottom chord. The bridge is extremely well preserved, and it is one of the most distinctive early RR spans in the area.

Physical Description: The 9-panel Howe pony truss bridge is supported on concrete abutments built in 1917 (south) and 1933 (north). The members are wrought iron, and all connections are riveted. Although moved to this location in 1933, the trusses appear to be entirely original. They are of unusual, massive design with the inclined end posts, top chords, and bottom chords of double-web plate each with two angles which connect to a cover plate. At the bottom (open) edge of the web plates of the top chords there are unusual corrugated plate instead of the more common detail of lacing. Each truss panel is composed of two diagonals in the pattern of an X. The tension diagonal consists of four angles in two pairs riveted to the chord web plates outside the line of the double webs. The compression diagonals, which pass through the tension diagonals, consist of four angles in an H configuration with closely spaced lacing in the webs. Except at the first interior floor beam, there are no verticals, but there are knee braces which extend from the top flange of the floor beams to the inside web plate of the top chord. Another unusual detail is the haunched roadway profile which is achieved by varying the floor beam attachment points. At the abutments the stringers sit on a timber bridge seat rest on the back wall which is depressed so that the roadway surface is lower than the bridge bearings. The first interior floor beams are riveted to the underside of the bottom chords while the remaining floor beams frame into the inside web plates of the bottom chords.

Historical and Technological Significance: The wrought-iron Howe pony truss bridge is technologically significant as a rare survivor of its type, being one of the oldest and most complete railroad-related pony truss spans in the state (criterion C). The various plans and shop drawings that survive offer an interesting chronological history of the crossing and the trusses. Prior to 1896 the Easton & Amboy Railroad, a subsidiary of the Lehigh Valley Railroad, had constructed a 3-span timber pony truss bridge over its two-track line. A plan prepared for or by the Easton & Amboy Railroad dated April 4, 1896 shows the addition of a new masonry and timber bent at the line of the original south abutment, and the construction of a new stringer end span that allowed the excavation under the original south end span to accommodate a third track. The Easton & Amboy line became known as the Lehigh Valley Railroad. In 1916 the LVRR designed a reinforced concrete south abutment and a new timber pony truss bridge that eliminated the short south end span added 20 years earlier. The inscription on the south abutment reads "1917" showing that it was built the year after the date on the plans. Plans dated March 21, 1933, indicate that the Lehigh Valley Railroad replaced all of the timber pony truss span except the 1917 concrete south abutment. The work was done in 1933 and 1934. The 1917 abutment was raised with a new concrete seat. The north abutment is a gravity type. The most significant feature of the 1933 "upgrading" of the crossing is that the Howe pony trusses installed to replace the timber trusses. The iron trusses were fabricated in 1891 by the Philadelphia Bridge Works. They are a pair of the six "side trusses" fabricated for the LVRR for the "Stanton Bridge" (bridge 53-A) in Hunterdon County. The Stanton bridge was removed and the trusses were in storage. While the trusses are old, the rolled floor beams, stringers, and timber plank deck were new in 1933. The plans show that the floor system was designed for a strong of 15-tone trucks (similar to today's H-15 loading). The 1891 truss lines were checked for this load in 1933 and found to have great excess capacity. A notation on the 1891 Philadelphia Bridge Company shop drawing specifies that six "trusses like this" were wanted. From the size of the section of the truss members, it is clear that the trusses were built to carry rail traffic, not vehicular traffic. The shop drawings give no material properties, so the note that the trusses are wrought iron is not confirmed. The 1891 trusses survive basically unaltered, and they rank among the oldest and most complete railroad-related pony truss spans in the state. The Philadelphia Bridge Works was started in 1877 by Cofrode & Saylor. Their shop was located in Pottstown. The 1898 Philadelphia city directory list the owners of the company as C.R. Baird and Company and that the plant was idle and for sale. It was purchased by the Pottstown Bridge Company who subsequently sold to McClintic-Marshall in 1900. The Pottstown works were on the location of a former repair shop of the Philadelphia and Reading (Reading) Railroad.

Boundary Description and Justification: The bridge is evaluated as individually distinguished. The fact that it was moved does not detract from its technological significance. It is the trusses that are the important part of the resource, and the boundary is limited to the trusses themselves.

Discussion of Surrounding Area

The bridge carries one lane of a quiet rural road over one track of the Lehigh Valley Railroad. It originally crossed three tracks. It is located in a lightly wooded suburban setting dominated by large homes on generous lots. The bridge is at the intersection with Staats Road.

HISTORIC BRIDGE MANAGEMENT PLAN ( EVALUATED ) Yes

Bridge Considered Historic By Survey: Yes