New York City commuters should expect long delays and large crowds on Metro-North Wednesday after a four-alarm fire broke out beneath elevated train tracks in East Harlem.

At a press conference Wednesday morning, MTA Chairman Thomas Prendergast said the commuter line would remain on a Saturday schedule, and that that regular service isn't expected to return before Friday.That means fewer trains than usual will be running as Metro-North personnel continue to repair a damaged section of the tracks.

Trains will stop in the Bronx so passengers can connect to subway service in Manhattan. NJ Transit is also cross-honoring Metro-North Hudson Line tickets.

Officials say the massive blaze ignited Tuesday night at a garden supply business underneath the Metro-North tracks at 118th Street and the Park Avenue viaduct. The fire halted service and stranded thousands of commuters.

More than 150 firefighters responded to the fire. One firefighter suffered a minor injury when he slipped, but no civilians were hurt.

The fire is still under investigation.

For service updates, check out the MTA's website.