Update: Most trains in Manhattan are now running "very well," lettered trains in Brooklyn have delays, and bus service is limited around the city, MTA chairman Jay Walder said Monday afternoon.
Long Island Railroad trains have been suspended, and Metro-North is operating with limited service, he said at a news conference with Mayor Michael Bloomberg.
Walder warned that even as crews work to dig out tracks and bus routes, Tuesday's morning commute will be difficult.
"Service tomorrow will still not be a walk in the park," he said. "It will be a tough day."
Earlier: The post-Christmas blizzard that brought upwards of 20 inches of snow to Central Park and wind gusts of more than 35 mph has also made a mess of public transportation Monday with all 21 subway lines undergoing service changes or delays.
It was not immediately clear when service would return to normal, but transit officials were advising New Yorkers to stay at home if they did not need to go out.
"We have no (estimated time) for restoration of service that is currently out," MTA spokesman Charles Seaton said. Most bus lines are also experiencing delays because of street conditions.
Any inconvenience Monday straphangers faced would likely not be as bad as those who were stranded overnight on four A trains for seven hours.
"I wanna go home!!!" rider OMjohnnyG tweeted several hours into the ordeal. "Dudes on the train talking about cannibalism lol I want out!!!
Snow and ice covering track third rails knocked out power around 1 a.m., stranding 400 passengers on a train near Aqueduct Racetrack and 75 riders on trains near the Broad Channel stop in the Rockaways, MTA spokeswoman Marjorie Anders said.
She disputed reports that passengers were trapped in the cars. The trains were partially pulled into the stations, and people could have exited if they wanted, she said.
"The doors could be opened if they needed to get out," Anders said, adding that employee restrooms were available at the stations for passengers. The trains were finally moved around 8 a.m., she said.
Other train and bus problems, blizzard conditions and employees who had trouble getting to assignments caused the 7-hour wait, Anders said.
Riders on the A trains weren't the only ones who had a sleepless night.
Margie Chen, 19, of Brooklyn said she got on the D train in Manhattan around 10 p.m. and didn't get home until 6 a.m. Monday.
The train was stuck between the 36th Street and Ninth Avenue stations for two hours, Chen said, before sitting at the Ninth Avenue station for several hours.
"When we were underground, I heard the conductor saying someone was freaking out," she said.
She added that "even if you tried to sleep you couldn't because you were hoping in the next five minutes you would pull into your train station."