The first bridge on the MW&W, the Avogadro Creek Truss bridge, remains the scenic highlight of the line and was put in service in the fall of 2009. It was designed, manufactured, and assembled by the Waynesville Bridge & Iron Works (WVBI) of Waynesville, Illinois and Zephyrhills, Florida. It is four feet long, made of aluminum with stainless steel screws in tapped holes. The primary design requirement was that all bridges on the MW&W would have strength and clearances for a type K-27 Mikado locomotive. This requirement was verified by successful testing in the summer of 2011. Triple headed K-27s have traversed the line with no problems.
Avogadro Creek Dry Wash
In the early summer of 2010, WVBI delivered a two foot long plate girder bridge designed to connect directly to the west end of the truss bridge. The girder bridge crosses the lower loop and bridges a dry wash on the west bank of Avogadro Creek. Along with the girder bridge, WVBI delivered three support towers to support the truss and girder bridges.
Flat Girder Bridge
At the same time the girder bridge and towers were delivered, WVBI delivered a flat girder bridge to carry the main line over the lower loop west of the Avogadro Falls Depot. The bridge is on a curve and to facilitate clearance, no structure is higher than the height of the rail.
A wooden truss bridge was built by the MW&W based on the WVBI truss bridge design and put in service in early 2011. It was three feet long and carries the west portion of the upper loop just west of the Willoughby Depot. In 2013 the bridge had become unable to maintain structural integrity and track geometry. A Board Member discovered a severe lack of clearance problem between the bridge and the cab windows of the K-27s. The bridge was promptly removed from service late in the 2013 season and replaced with a new four foot span built to higher standards.
The present 12' aluminum undergirder bridge over Avegadro Creek just east of the falls replaced earlier structures and was built by the MW&W with design fabrication consultation from WVBI. There is a short support tower between the two six foot spans on the north bank of Avegadro Creek.
Avogadro Creek approach span
A 12' span, which previously served as the Avegadro Falls bridge, was placed in service in late 2011. It is supported by four towers built by MW&W based on the WVBI tower design. These towers suggest the look of the D&RGW Cascade and Lobato trestles. In 2012, this span and tower scheme was extended to the North Willoughby Junction.
A new six foot long wooden truss bridge carries the expanded (in 2014) lower loop across a dry creek bed. The design is similar to the West Willoughby bridge. The bridge is constructed from cedar and poplar.