When the train doors opened, "quite a lot of water came in, so almost all of us stood up on the seats," a passenger told Newsweek.

Flooding caused delays on multiple New York City subway lines Monday as torrential rain pummeled the Tri-State Area, where many were under flash flood warnings. MTA Chair and CEO Janno Lieber says riders can expect normal service for the morning commute Tuesday.

The subway system, which is more than a century old, is relied on by millions of passengers every day and weaves the city into a cohesive network.