New York ? A crude sketch of Grand Central Terminal was found at the home of a suspect in the Madrid train bombings, but was not considered cause for alarm, New York City’s police commissioner said Wednesday.

The one-page, hand-drawn document “was a very basic schematic,” Commissioner Raymond Kelly said. “It’s not an operational plan. It’s not something that would indicate an immediate threat.”

The Spanish newspaper El Mundo reported that the drawing and other data were on a computer disk seized about two weeks after the train bombings in Madrid that killed 191 people on March 11, 2004. Spanish police turned the disk over to the FBI and CIA in December.

Kelly said the data — found on the disk of a laptop computer — also was shared with the New York Police Department’s counterterrorism division and city transit officials, who concluded the sketch depicted Grand Central.

The material also included photographs, and a drawing of a private building in the city, which Kelly refused to identify. But an analysis found no indication of a terrorism plot, and authorities quickly decided there was no need to alert the public, he said.

“We didn’t see it as a threatening piece of information,” he said.

Wednesday at Grand Central, security appeared to be at a high level as usual, with National Guardsmen, law enforcement officers carrying machine guns, and bomb-sniffing dogs.

“I’m used to this,” said Elaine Weaver, a tourist from Bristol, England, who was passing through the station. “We’re used to bomb scares everywhere. So you’re careful but it doesn’t deter me.”

The NYPD’s intelligence division studied the bombings in Madrid as a possible template for a New York attack. The department responded by tightening security in the subways and at commuter train stations. Those measures were in place long before the city received word of the sketch.

“This is not something I think people should be panicked about or worried about,” Mayor Michael Bloomberg said. “We took the appropriate steps and we do not think that in that particular case there was a real plan to attack Grand Central.”

There were conflicting descriptions of what the drawing showed. A Spanish police official said it depicted a facade similar to that of Grand Central; Kelly said it showed only the building’s interior.

The same Spanish police official, who spoke on condition of anonymity, said that the sketch was found in the home of Mouhannad Almallah, a Syrian arrested in Madrid on March 24. He was later released but is still considered a suspect.

Almallah was questioned over his alleged ties to two suspects jailed in connection with the attack, El Mundo said. Twenty-four people are in jail over the attack, and at least 40 others who were arrested and released are still considered suspects.