The dreaded "signal problems" caused headaches for subway riders again Monday as the "summer of hell" got officially underway.
Signal problems at Prospect Avenue caused delays on uptown 2 and 5 trains for a time, while signal problems at 50th Street delayed A, C and E trains. Those problems cleared around 6:15 a.m., but delays lingered.
In Pictures: An Inside Look at the First Day of 'Train Pain' Across the Region
Later in the morning, a track test train operating on the express tracks between Jay Street-MetroTech and Inwood-207th Street caused major delays on E and F trains. The MTA tweeted an apology shortly before 11 a.m., saying, "crews are working to restore the lines to good service."
It's the latest blight in a series of problems, ranging from minor switch issues to a derailment in Manhattan, plaguing the MTA. Tens of thousands of subway riders have been stranded on jam-packed trains and overcrowded platforms in recent months as the 112-year-old system's aging infrastructure buckles under increased ridership. And ridership volume is only expected to rise during the work at Penn.