Wabash Trace Nature Trail - Silver Creek Bridge

Located between Malvern and Silver City, this historic through truss bridge carries a former Wabash Railroad branch line over Silver Creek. The first bridge at this location consisted of a timber pile trestle, last renewed in 1902. In 1923, the original bridge was rebuilt using a secondhand through truss span, set onto timber pile piers and retaining the timber pile approaches. In the 1930s and 1940s, the Wabash invested capital into this line, renewing select timber bridges with steel spans. In 1934, the approaches were rebuilt with steel stringer spans set onto timber bents, giving the bridge its present configuration. Currently, the bridge consists of a 128-foot 11-inch, 6-panel, pin-connected Pratt through truss span, approached by one 24-foot steel stringer span on the south end and eight 20-foot steel stringer spans on the north end. The entire bridge is set onto timber pile substructures. Pencoyd Bridge & Construction Company (A&P Roberts Company) fabricated the truss span, while an unknown contractor fabricated the approach spans. It is believed the timber components were constructed by railroad company forces. The truss span was originally fabricated in 1892 for use as span "F" of Bridge #665 across the Wabash River at Attica, Indiana. Originally, that bridge consisted six through truss spans of varying lengths. In 1914, a serious derailment destroyed spans "A" and "B" of the Attica bridge. In 1922, the remaining four truss spans were replaced and released for reuse on branch lines. Spans "C" and "D" were reused at Bridge #2891 across the Des Moines River near Harvey, Iowa, while it is believed that span "E" was reused at Bridge #1053A on this line, which crossed the 102 River near Maryville, Missouri. Bridge #1053A was scrapped after this line was abandoned, while Bridge #2891 remained intact until 2025, when a sinking pier collapsed the bridge.

The truss span follows a standard design for the era, with built-up members, a standard floor and lattice style portals. The top chord and endposts both consist of built-up beams, which are formed from two U-shaped channels connected by X-lacing on the bottom and solid plates on the top. At the center two panels, the bottom chord is constructed using two eyebars, while the bottom chord at the outer panels uses a unique V-laced beam. The vertical members of the truss are formed from tightly V-laced beams, while the diagonal members are formed from eyebars. The counter members are formed from thin rods and turnbuckles. The floor system uses four light stringers, arranged into two sets of two. These stringers are supported by hangers on the plate girder floorbeams. The floorbeams are connected to the vertical member by rivets, and the lower lateral bracing is constructed of L-shaped bars. The portal bracing consists of a thin lattice bar and diagonal heel bracing, which are built using L-shaped bars. The sway bracing uses a V-laced bar, while the upper lateral bracing uses a square bar. Minor alterations appear to have been made to the truss, including additional rivets at the endposts. The approach spans follow a standard Wabash design, with four shallow beams arranged into two sets of two. Typical of Wabash steel stringer bridges from this era, the spans appear to be semi-continuous, and are connected by a plate at each joint. The main piers are constructed of heavy timber piles, while the remaining substructures are constructed of standard timber pile bents. To help stabilize the creek banks, scrap boxcars were added to the banks in the mid-20th Century. Although badly deteriorated, these scrap cars remain intact today.

The Pratt truss pattern was arguably the most popular railroad truss bridge design during the second half of the 19th Century. This design was simple, durable, strong and economical. The design remained popular until around the turn of the 20th Century, when it was largely superseded by riveted Warren trusses, which were stronger while retaining simplicity. Railroads often reused steel and iron spans, as it provided a cost effective way to upgrade bridges without requiring large amounts of new material. Many of the steel bridges on this line were constructed using secondhand material. Steel stringer spans were also popular for railroad use, as they were durable and easy to construct. The Wabash used steel stringer spans extensively, especially in place of traditional timber stringers supported by timber piles. Typical of most bridges along this line, the substructures are made from timber components, which provided a cost effective material. Since the initial construction, the bridge has seen no significant alterations. A timber deck and railings were added to the bridge, and it now carries the Wabash Trace Nature Trail. Overall, the bridge appears to be in fair condition, with some deterioration noted to the timber components. However, the truss and approach spans appear to remain in good condition. Should the bridge eventually require significant maintenance, any rehabilitation should seek to preserve the superstructure. One possible solution could include replacing deteriorated timber piles with steel piles, while retaining the original superstructure. The author has ranked this bridge as being regionally significant, due to the truss design, age and history.