Some called it the shadow race. Others the underground marathon. Plenty of people did not know what to call it at all.

But on what was scheduled to be Marathon Sunday, thousands showed up early in Central Park to run on a crisp and clear fall day despite the cancellation of the New York City Marathon on Friday.

Race organizers and city officials initially said that they planned to hold the marathon as scheduled, saying that it would provide a powerful unifying moment for a region reeling from Hurricane Sandy. But opposition turned into a roar by Friday, and the event was called off, leaving thousands of runners all dressed up, from sneakers to sweatbands, with no race to run.

The traditional blue-and-orange finish line was still set up on the park’s west side, as were portable toilets, orange bleachers and a press box. All of it came into use Sunday morning as security guards politely asked people to give some space to the cluster of runners. Fans lined a route around the park, clanging cowbells and clapping and cheering as if they had not received the news about the change of plans.