But the system’s descent into chronic unreliability has become so embedded in the psyches of riders that many are overcompensating, adding extra time to their trips. In one of the more counterintuitive conundrums to emerge from this confounding city, the subway has been making people early.

Still, just because on any given day the subway may offer an on-time surprise does not mean riders will be pleased. “Because then you hate that you’re there early,” said Adanna Roberts, a hair stylist who builds in an extra 30 minutes to travel from Brooklyn to work in Midtown Manhattan.

While delays and failures — broken-down trains, malfunctioning signals, sick passengers and track fires — are extensively tabulated, no one (perhaps unsurprisingly) keeps statistics on when the subway gets riders to their destinations on time.

“You make that sacrifice to get up extra early to be at work, and if then you get there early, nobody is going to recognize that — but if you’re late, it’s an issue,” said Eduardo Andrade, who lives in Williamsburg, Brooklyn, and works as a custodian at Lincoln Center. He has rearranged his family’s life around the subway, making his two children go to bed an hour earlier so he can wake up earlier and give himself more time for the ride to Manhattan.

Subway riders have good reason to assume the worst. Despite an infusion of hundreds of millions of dollars and an emergency turnaround plan heavily promoted by Gov. Andrew M. Cuomo, who controls the subway, the system is still faltering — in January it fell to a new low with just 58.1 percent of all weekday trains arriving at stations on time. Weekends were not much better, with 64.7 percent of trains reaching their terminus on time, a nearly 10 percentage point drop from January 2017.