A series of robberies on the Midtown Greenway bike trail in Minneapolis has prompted more volunteers to mount up and help keep the trail safe.

Three bicyclists on the Greenway were robbed during three different incidents recently. Officials with the Midtown Greenway Coalition, a member-supported group, say that kind of violence is rare.

The coalition estimates 4,000 to 5,000 people ride the trail every day. And the group's website lists 20 violent incidents that it's heard of since 2011. Besides the recent robberies, the only incident this year occurred in July, when a bicyclist reported being punched in the face by a juvenile.

Trail Watch volunteer Kurt Lach said he feels safe when he rides at night. But he sees too many people who put themselves at risk.

"I see a lot of people, a lot of young men and young women, riding their bikes late at night with headphones on," he said, "riding no-handed, texting on their phones, totally unaware of what's going on."

Greenway Coalition officials said a series of robberies of cyclists along the nearby Hiawatha LRT trail led to the formation of Trail Watch seven years ago.

Volunteers with Trail Watch do much more than look out for potential troublemakers. They are more likely to stop and pick up broken glass from the trail or help stranded cyclists than to call 911. Most nights on the trail are pretty uneventful.

Trail Watch riders wear helmets and reflective florescent vests. One of them, Neal Axton of St. Paul, also wears a bulletproof plate over his chest — although he figures it would be more likely to protect him in a collision with a car than from gunfire.

Kurt Lach strapped on his helmet before riding the Greenway while Gary Davis looked on. They were part of a group of bikers who volunteered to patrol the Greenway on Sept. 9, 2015. Brandt Williams | MPR News

Axton started patrolling the Greenway four years ago, after he heard about an attempted sexual assault along the path. He said the statistics show much more crime on nearby Lake Street than on the Greenway.

"Certainly, I feel safer on the trail than I do riding on Lake Street, with the potential for robberies — as well as the cars," he said.

The recent robberies all happened late at night, past 11 p.m. One of the victims, 27-year-old Ricardo Zamora-Mascada of Minneapolis, said he was riding home from work when two men stopped him and forced him off his bike at gunpoint.

Zamora-Mascada said the robbers threatened to kill him. Then they took his cellphone, his wallet and his backpack — but not his bike. Zamora-Mascada said he's not going to ride on the Greenway after dark anymore.

Minneapolis police officials said they've made no arrests in connection with the robberies, but have increased the number of officers on bikes and in squad cars patrolling on and near the Greenway. The Midtown Greenway Coalition has hired private security personnel to ride the trail late at night. And they encourage people willing to help to sign up for Trail Watch.

The Greenway, which stretches five and a half miles through Minneapolis, is nationally recognized as one of the most scenic urban trails for biking and walking in the country.