The collision happened about 1:10 p.m. on the Mary Carter Greenway Trail near South Prince Street and the South Platte River, said Littleton police Sgt. Arlan Kluth.

Both victims were wearing helmets, Kluth said.

The men were taken to Swedish Hospital, where the 60-year-old cyclist, identified as Thomas Fox of Jefferson County, was pronounced dead. The other man, who is 35, was treated for injuries and released, Kluth said. His name was not available.

The bike trail's speed limit at the accident scene is 15 mph.

Fox was riding behind two other cyclists, all in single file, and heading north on the trail, which is about 5 feet wide where the accident happened, Kluth said.

The injured bicyclist was heading south and riding alone.

As the four converged, the lead bicyclist in the group of three called out to the southbound bicyclist, apparently to get his attention.

The southbound bicyclist missed the first northbound rider, brushed shoulders with the second and collided head-on with the third.

"It's kind of a blind curve," said Sgt. Sean Dugan, a Littleton police spokesman.

"Riders in either direction aren't able to see a rider approaching from the opposite direction because of the curvature and the grade of the bike path."

It is doubtful that charges will be filed, Dugan said.