The sketch and data were on a computer disk seized about two weeks after the March 11 train bombings in Madrid that killed 191 people last year, the newspaper El Mundo said.
However, CBS News Correspondent Sheila MacVicar reports one Spanish source has said that neither Spanish authorities or U.S. officials put much credence in the sketch, saying it doesn't look very much like Grand Central Terminal.
In New York, Mayor Michael Bloomberg said the FBI had informed the Police Department about the existence of the data on the computer and the city responded by tightening security at transit centers.
"We've known about the data on the computer for a long time," said Bloomberg, interviewed on WBLS Radio.
"We've taken the appropriate steps 'back when' to beef up security at all of the major transportation hubs — train stations and airports and bus stations, places where you say if a terrorist wanted to attack, they would," Bloomberg said.
"We looked at all of our transportation facilities and we think we've taken appropriate steps. ... It's sad we're in a world where you have to worry about it, but you do," he added.
Spanish police turned the disk over to the U.S. agents from the FBI and CIA in December once they understood the scope of the technical data, the report said.
On Wednesday at Grand Central, visible security seemed at its usual high level, with National Guard, machine-gun-toting law enforcers and bomb-sniffing dogs.
"I'm used to this," said Elaine Weaver, a tourist from Bristol, England, who was passing through the terminal. "We're used to bomb scares everywhere. So you're careful but it doesn't deter me."
A U.S. Embassy official confirmed that American law enforcement authorities received information related to Grand Central Terminal from Spanish authorities in December. The official declined to go into detail.
The police official, who spoke on condition of anonymity, confirmed the sketch was found in the home of Mouhannad Almallah, a Syrian who was arrested in Madrid on March 24 but later released, although he is still considered a suspect.
Almallah was questioned over his alleged ties to two suspects jailed in connection with the attack after witnesses placed them aboard trains targeted in the string of 10 bombs, El Mundo said.
A total of 24 people are in jail over the attack, although at least 40 more who were arrested and released are still considered suspects.
After the Madrid attack, security around New York City's subways and commuter points, such as Grand Central and Penn Station, were ratcheted above the already-high post-9/11 levels.
Peter Kalikow, chairman of the Metropolitan Transportation Authority, said at the time that the chance of a transit attack in New York was "diminished, but possible." He added that if an emergency occurred, "100 guys would show up right away." He refused to disclose exact numbers.
Kalikow also said the MTA's chief of security had been in London at the time of the Spain bombing and was sent to Madrid to observe the situation.