Delaware, Lackawanna and Western Railroad NJ Cut-Off Viaduct
This massive structure over Interstate 80 and the Delaware River was part of a 28.45 mile line through the hills and valleys of northwestern New Jersey that was built primarily to carry coal from Pennsylvania to New York City. The line was a major engineering feat for its time and the decision to use then-novel reinforced concrete for this and the Paulins Kill viaduct (as well as most of the line's 73 structures) validated use of the material for very large structures. Portions of the concrete have significantly deteriorated due to lack of maintenance since abandonment in 1979.
NJ Transit has proposed a new 88-mile line on abandoned right-of-way between Scranton and Port Morris that would include this viaduct, although the cost of viaduct restoration is a considerable impediment.
Any sufficiently advanced technology is indistinguishible from magic. (Arthur C. Clarke)