Bloomberg News/Businessweek ran an extensive piece about the potentially disastrous condition of Penn Station in New York City and the perilous state of the two Hudson River tunnels that feed it. The tunnels are over 100 years old. The construction fill from the original World Trade Center that was used to create new land changed the course of the Hudson in such a way as to erode the river bed above the tunnels. Hurricane Sandy partly filled the tunnels with salty water, and the salt deposits are eating away at the elderly concrete.

The tunnels now carry far more people than they were ever envisioned to carry into the busiest single train station in the United States, so closing them for repairs would congest commuter traffic horribly, and projects to construct newer tunnels to supplement these aging ones have never come to fruition. So the author of the piece, Devin Leonard, details in his article:

As the gateway to America’s largest city, Penn Station should inspire awe, as train stations do in London, Paris, Tokyo, and other competently managed metropolises. Instead, it embodies a particular kind of American failure—the inability to maintain roads, rails, ports, and other necessary conduits. For generations, the officials connected to Penn Station have been blind to, or unable to deliver on, the idea that improving the station would more than pay for itself. (One estimate, from the Business Roundtable, says that a dollar invested in infrastructure yields as much as $3 in economic growth.) In the final days of 2017, the situation reached perhaps its bleakest point yet, when the Trump administration signaled its disinterest in coming to the rescue: The president will not honor an Obama-era commitment to New York and New Jersey to foot half the cost of a new tunnel, dumping planners back at square one. [emphasis mine]