What to Know New Yorkers on the subway kicked off their weekends dealing with long delays to go with the blazing hot temperatures

The MTA reported that 1, 2, 3, 4, 5 and 6 trains all faced delays due to a network communications issue impacting service in both directions

Over an hour after initial word of the disruption, the MTA said the effected computer system that controls signals was running once again

Dude, where's my train?

New Yorkers taking the the subway kicked off their weekends dealing with long delays at the peak of the evening commute to go with the blazing hot temperatures — because the MTA didn't know where the trains exactly were.

The MTA reported at 6 p.m. Friday that the 1, 2, 3, 4, 5 and 6 trains — nearly a third of the city's lines — were all facing delays due to a network communications issue impacting service in both directions. The shuttle between Times Square and Grand Central was also affected by the disruption.

The president of the New York City Transit Authority, Andy Byford, said Friday night that "we did not know exactly where our trains were, so for safety reasons, we had to ask all trains, to instruct all trains to stop where they were, to maintain their positions while we ascertained what exactly was going on such that we could safely move trains out."

An MTA official said that it did not appear that power or weather had anything to do with the disruption. Service on lettered lines was not effected.

MTA Communications Director Tim Minton said in a statement that they don't believe any trains "lost power or AC during the outage ... Power for lighting and air conditioning remained on while service was disrupted."

About an hour and a half after initial word of the disruption, the MTA said that the effected computer system — which controls signals for the subway lines — was back up and running. Riders should still expect extensive delays as the agency got trains running back to normal, and encouraged customers to use lettered lines and local buses.

Photos on social media showed massive crowds at different subway stations, including a line of people trying to get down the stairs to the platform at Grand Central on the 4,5,6 lines and a packed platform at 96th and Broadway on the 1,2,3 lines.

"This kind of meltdown during a heat wave is UNACCEPTABLE," NYC Mayor de Blasio tweeted while trains were not running. "The MTA owes every single New Yorker an explanation for this. We've known about this dangerous weather for DAYS. There’s no excuse for why they aren't prepared."

New York City Comptroller Scott Stringer called the situation "completely unacceptable."

"Service is suspended and platforms are boiling. New York cannot function like this," Stringer tweeted.

NYC Council Speaker Corey Johnson echoed those sentiments, saying he will be "expecting a report from the MTA on how this happened during a heat wave when people are encouraged to use mass transit."

Some passengers on trains at the time were told to get off the train and wait at the sweltering stations. Other rides complained about being stuck on the subway and not moving, without being told what is going on.

The NYPD dispatched additional officers to manage extreme crowding on subway platforms, according to de Blasio.

A similar network error impacted the same exact train lines earlier this month. During the later morning of July 6, a "network communications issue" halted service temporarily on the 1-6 lines.

An investigation into the root cause of the system failure is ongoing.