Here are the most common reasons why an MTA train is running late, and the most delayed lines in the NYC subway system.

The Monday morning rush hour was upended on New York City’s subway after multiple train lines faced rolling delays — some of them “severe” — according to the MTA. The transit agency said at one point ...

Shortly before today’s push, I sat down with Shanifah Rieara, the MTA’s chief customer officer, for a first look at its replacement, and I offered her a version of those observations about the old app ...

The morning commute may take longer than usual, as several subway lines are running with severe delays or have been rerouted.