As increasing delays and other problems in the city’s subway system have reached a breaking point, the story of why New York, the economic capital of the world, employs subway cars long past their expiration date is illustrative of many issues plaguing the region’s transit infrastructure and why fixes are hard. The tale of the Brightliners, and how difficult it has been to replace them, perfectly exemplifies the challenges, missed opportunities and lack of resolve — both political and financial — that have caused the system to arrive at the verge of collapse.

And unlike the power substations or the signals or other vital parts of the underground infrastructure that routinely fail, the Brightliners are not hidden from view.

Instead, for straphangers taking a bumpy ride on one of the old cars, they are like time machines transporting them back to an industrial past when the future of urban transit seemed full of possibility and potential — and a reminder of how long ago those days now seem.

Keeping the 53-year-old trains running is not just an aesthetic problem. The cars, also known as the R32, break down far more often than any other train in the system, averaging just 33,527 miles between failures. The average subway car can travel 400,000 miles before breaking down. And the newest cars in the fleet average more than 750,000 miles.

When a car breaks down, it can have a ripple effect that quickly radiates throughout the system and is one of the many reasons that riding the subway has become increasingly unbearable.