Investigators say a fuel spill sparked the massive fire under part of the Metro-North tracks in East Harlem.

Flames broke out just before 7 p.m. Tuesday at the Urban Garden Center on Park Avenue near 118th Street.

Fire officials say fuel spilled on a generator while it was being filled, which caused flames to reach under the elevated tracks.

It took more than 160 firefighters about two-and-a-half hours to get the flames under control.

NY1 spoke with residents in the area, who are concerned about the Garden Center's location.

"I just feel like there's a little bit of negligence here. The materials that were found there is what you have to make a bomb. So how can this be, especially under the Metro-North? I just don't even understand it," said one resident.

"It's dangerous," said another. "You're having all this garbage, having all this wood, just collectable stuff. It shouldn't be."

Repairs are underway, but Metro-North says commuters should still expect delays.

Trains are running on an enhanced Saturday schedule Thursday.

Only two out of the four tracks are working, so trains are running at half their normal speed.

For the latest service information, go to mta.info.