Michigan City Railroad Bridge - Michigan City, Indiana
N 41° 43.359 W 086° 53.871
16T E 508496 N 4618988
The Michigan City Railroad Bridge is a Metal Pin-Connected Pratt Through Truss Movable, Swing (Center Pier) bridge. It carries the Norfolk Southern and Amtrak trains over Trail Creek in La Porte County, Indiana.
Waymark Code: WMM71J
Location: Indiana, United States
Date Posted: 08/02/2014
Views: 1
Information and Findings From: DHPA Historic Bridge Survey (Division of Historic Preservation and Archaeology)
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Statement of Significance
The truss designer appears to have followed some of Waddell's 1898 prescription that 225'-300' swinging spans ought to be designed as pin-connected Pratt throughs with broken top chords. The reduced use of pins here reflects early twentieth century experience with the extra wear moving spans put on pin connections. This bridge appears to retain its original members, including power source and latticed portals. It is the only structure of this design remaining in Indiana.
Architectural Description:
New York Central trains have crossed Trail Creek over a rim-bearing, partly-pinned Warren through swing span for decades. The top chord is raised in the panel over the rim and connects to the four-panel side sections through heavy die-forged eyebars. Both chords and endposts are fabricated from laced crafted channels. The diagonals crossing the 4th and 6th panels match the outer endposts and include latticed portals; heavy eyebars in the 3rd and 7th panels carry the stresses from the raised central panel; laced crafted channels serve in the 2nd and 8th panels; and a diagonal inserted about one-third of the way up the endpost stabilizes the abutment panel. Pins are used only for the top 3rd, 4th, 5th, and 6th and the bottom 2nd and 7th panel points whose connecting die-forged eyebars carry the extra tension of the ends when the truss is turned. Rectangular girder floor beams carry the timber tie deck and its single track.
Bridge Considered Historic By Survey: Yes
The bridge was built ca. 1905.