Wall Street is open for business today, but it won’t be easy for traders to get to work. The New York City subway system remains shut down in the wake of flooding from Sandy.

Transit authorities say it’s the worst crisis for the subway system in its 108-year history. Repairing the system is likely to be a huge challenge for the city; some pieces of equipment are so old that finding replacement parts could be a challenge

“This is a system that is contantly leveraging itself to the max,” says Joshua Schank, president and CEO of the Eno Center for Transportation in Washington, DC. “They are trying to keep up the best they can, but something like this is a huge setback that is going to require a lot of extra funding.”

Furthermore, Schank says public transit systems are at risk if future storms hit: “We really haven’t been accepting the fact that climate change has dramatically changed how our facilities are going to operated and repaired.”