PORTLAND — Flashlight beams cut through the darkness, illuminating a stone bridge overhead and piles of trash on either side of what used to be an active rail line.

“Hello, is anyone there?” shouts Missy Leeman, a human services counselor for Portland’s Oxford Street Shelter.

No one answers – a good thing, from Leeman’s and Josh O’Brien’s perspective. The abandoned rail tunnel, a few hundred feet from the Casco Bay Bridge, is a popular place for the homeless.

“It’s a success if we don’t find anyone,” said O’Brien, director of the Oxford Street Shelter. “But if we didn’t get into some of these places and make sure that no one is living there … that would be a disappointment for us.”

O’Brien, Leeman and William Burney, field office director for the U.S. Department of Housing and Urban Development in Bangor, were one of five teams that set out on foot and in vans Wednesday night to look for people living outdoors. The goal was to provide a snapshot count of Portland’s homeless population.

The results take a few weeks to compile. Last January’s survey identified 338 people staying in emergency shelters, and only two living on the streets.

The city must do the annual Point in Time survey to keep receiving funding from the Department of Housing and Urban Development. Burney said the data that is collected is evaluated by HUD and used to ensure that Portland’s homeless residents are getting the services they need.

Last year, HUD provided $2.9 million for employment assistance, job training, development of affordable housing and emergency shelters in Portland.

“We feel Portland is at the forefront of fighting this problem,” Burney said. “We feel it is a solvable problem. It’s not going to be easy, but it can be solved.”

Information from Wednesday’s survey will be used by the city’s new Taskforce to Develop a Strategic Plan to Prevent and End Homelessness.

The survey includes interviews with people in the city’s six overnight shelters and homeless people found by field survey teams.

As of 9:30 p.m., O’Brien said his teams had encountered 10 homeless people who were living outdoors, including seven at the Occupy Maine encampment in Lincoln Park. Two of the 10 people agreed to spend the night at a shelter.

Temperatures on Wednesday night were expected to drop to around 20 degrees, according to the National Weather Service.

Wednesday’s survey was expected to last until at least 1 or 2 a.m.

O’Brien said survey teams went to places like the Fore River Parkway, Baxter Woods, Deering Oaks, Bayside and the neighborhood near the Cumberland County Jail.

Two years ago, O’Brien said, the city found a couple who were in their 60s, living in a tent behind the Portland Star Match Co. building on Commercial Street. It took several visits to build up enough trust, but social workers persuaded the man and woman to abandon their tent for a shelter.

O’Brien said many homeless couples don’t like shelters because they aren’t allowed to stay together.

Eventually, the city found housing for the couple.

The open land between the Portland Star Match Co. building and Benny’s Fried Clams, where O’Brien’s team walked Wednesday night, is isolated. A snow-covered trail has tall stands of bamboo and pine trees, perfect cover for a camp.

O’Brien’s flashlight revealed a pile of rubbish and debris – a sign that someone had been living there.

In a prepared statement, Mayor Michael Brennan said, “The results we get from tonight’s Point in Time survey will be critical, as they give a voice to the hundreds of men, women and children experiencing homelessness.

“At a time when resources are diminishing and numbers (of homeless people) are increasing, it is clear that we need to do more for the city’s and state’s most vulnerable,” the mayor said.

Brennan said this is not the time to eliminate programs that help homeless people find stable housing or get life-saving health care.

Nicole Clegg, spokeswoman for the city, said the number of homeless people in the city has increased by 20 percent since the downturn in the economy started four years ago. On any given night, more than 350 people are homeless and seek refuge at one of the six overnight shelters.

There are now 65 family members, including a 3-month-old infant and a grandparent, living in the shelters. “This just shows that the impact of the economy is real,” Clegg said.