The commuter rail system that runs between Long Island and New York City is effectively shut down after 3,500 unionized workers went on strike early Saturday.The Long Island Rail Road, which is the largest and busiest commuter railroad in North America, serves roughly 300,000 riders daily. The strike is expected to hamper commuting for the foreseeable future.Five unions representing about half of the railroad’s workforce couldn’t agree on a pay increase in monthslong negotiations with the Metropolitan Transportation Authority. As a result, the strike took effect at 12:01 a.m. Saturday.

The MTA said its leaders will continue to negotiate with the unions, but the public transit authority urged riders to be flexible until a deal is reached. This means commuters may need to work from home.

“Unfortunately, there is no substitute for the Long Island Rail Road, and its shutdown will cause severe congestion and delays. Avoid nonessential travel and work from home if possible,” the MTA said in a statement. “If you must commute, give yourself ample travel time, no matter which mode you take. There will be congestion on the roads and travel alternatives will be near or at capacity due to an influx of additional riders.”