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.

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 century-old system is being hit with more powerful and frequent storms, and it will take a multiagency effort to fix it.