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More than 50 years ago, one of the main transit links between New York City and New Jersey was struggling to stay in business. It was saved by a political compromise between the governors of the two states.

Today, that rail network, known as the PATH, is as critical as ever to the region’s transportation network. It also loses more money than it ever did, piling up huge deficits that have made it one of the country’s most financially dependent public transit systems.

With more of New York’s workers settling across the Hudson River, the PATH is struggling to avoid being overwhelmed by rising demand. For the second consecutive year, it is on pace to carry a peak ridership of more than 82 million passengers on its compact network that connects Manhattan to cities in northern New Jersey. That’s up almost 10 million riders from five years ago.

Building has boomed around the PATH’s stations in New Jersey as developers have capitalized on access to a relatively inexpensive transit link. But the PATH’s popularity has not yielded any windfall for the system’s operator, the Port Authority of New York and New Jersey.