Tens of thousands of commuters were stranded for several hours yesterday after an abandoned building on 124th Street collapsed next to the Metro-North Railroad train tracks.

Fire officials said no one was hurt in the collapse of the five-story building at 102 E. 124th St., which crumbled to the ground at around 3 p.m. After a preliminary investigation, Buildings Department officials said all five floors had collapsed inside the building, along with two exterior walls. It said the city would begin demolishing the building immediately. Buildings officials also said they had issued a vacate order to the building next door, 100 E. 124th St., which they said was structurally compromised in the collapse. Both buildings were bought last year by the Kushner Companies, a spokesman for the real estate company, Howard Rubenstein, the president of the Rubenstein Associates public relations firm, said. After purchasing the building, Kushner moved out the previous tenants, the spokesman said. He said the building had remained vacant ever since as the owners prepared to renovate it.

“They thought it was old, and pretty decrepit, but they had no idea it was unstable, or they might not have bought it,” Mr. Rubenstein said.

Jared Kushner, who also owns the New York Observer, said through Mr. Rubenstein that the company had sent engineers to inspect the building three days ago in response to reports that bricks were falling from the façade. He said the company had then reported to the Department of Buildings that the building was in danger of imminent collapse, and that he believed buildings inspectors had been on site yesterday.

“There is no record to confirm that a call was made to DOB,” a spokeswoman for the Department of Buildings, Kate Lindquist, said. Since November, there had been six complaints lodged against the building’s owner for falling debris.

In December, the building owner was fined $800 for an A-level violation — the most serious — for a failure to maintain an exterior wall that had bulged, cracked, and shifted, according to the violation, which was filed in November.

On January 8, the Buildings Department issued another A-violation for a failure to maintain an exterior wall with hazardous defects. The violation noted that an approximately 20-square-foot area of a first floor wall had collapsed onto adjacent property. The second violation is pending. Ms. Lindquist said January was the last recorded time that inspectors had visited the site.

“Thank goodness no one was hurt. It’s quite unfortunate that this tremendous inconvenience was caused by the collapse,” Mr. Kushner said through Mr. Rubenstein, referring to the Metro-North delays.

Fire department officials said they had asked for Metro-North to halt its train service to prevent the track vibrations from destabilizing the building further while firefighters inspected it.

A spokesman for Metro-North, Dan Brucker, said all four tracks running north and south were shut down by 3:09 p.m. By 5 p.m., he said two tracks had been reopened, but that trains were restricted to speeds of less than 10 miles an hour.